Battle

"Taken from Mokafrap from Reddit verbatim."

How to Convert Battle Points to Progress
TL;DR Use battle points to play battles, to get rewards, to get good units, because BP regen.

Every time you level, your Ability Points(?)(AP) and Battle Points(BP) are refilled. You should use up your BP before you level. This is especially true when you level very quickly at the beginning. BP can be used in Battles and Raids. Both of them give rewards, but in a different way. I'd say Raids are for level 25+, when you start to deal more damage. So I'll only talk about Battles, as they're relevant throughout the game.

Battles
The rewards here are in-quest items (potions and feathers), spirit gems to buff units, and most importantly, gold/silver summons. Summons is one of the 4-ish ways to get better units, and perhaps the most realistic one despite being RNG.

There are 8 Battle time brackets each day, in PST:

You can get rewards at the end of every bracket. From each battle, you earn Victory Points(VP). Your points will rank you in comparison to all other players during the bracket. The higher you rank, the better rewards you get at the end of the bracket. The rank to rewards payout differs between brackets of different time durations, so just check in-game. You're looking to rank high enough for the summons, which is usually in the top 150, which isn't too hard. I'd imagine some brackets would have less people playing, making it easier. I don't have any data on that though.

What is a Battle?
A Battle is when you put your Raid Deck against another player's Raid Deck. A Raid Deck is a little different from the 5-man Quest Deck used in Quests. A Raid Deck is a group of several 3-man teams, or parties. When in battle one party from each side "goes into the ring" and fights. The surviving party stays with it's remaining living members and HP to fight the next opposing party. The Battle is automated, and continues until one side's entire Raid Deck is beaten.

At level 1 your Raid Deck will only have one party. Every 10th gives your Raid Deck gets an additional party, up to a total of 5 parites (15 units) at level 40. So don't sell off or feed units that aren't on your Quest Deck. You also want to fill your Raid Deck.

Pick your fights
On the Battle page, there will be a list of opponents you can choose to Battle. These opponents are real players, but you're only fighting their deck. They won't know if you choose to Battle them, and it does not affect their Win/Loss record. The W/L record is only for Battles players pick themselves.

Every opponent will have a VP. This is how many VP you will get if you beat them. This is calculated based on the deck's Total ATK and HP, and provides a way to judge how strong the team is. Because you can not look at the opponent's deck specifically, the only information you have is the player level, Total ATK and HP of the deck, VP for winning, and a single unit on that team shown by the leader image. Basically, pick an opponent with lower ATK and HP. However, this does not guarantee a win, as there are other factors in play.

Raid Deck unit positioning
Auto-build will choose units to place in parties in order of highest ATK, so the parties will go from the strongest to the weakest. When you get more parties in the Raid Deck, this might not be the best strategy.

For example, you may want to spread your put a stronger unit in each party, so none of them are full of weak filler units.

You could put a mediocre party first as fodder to die to and kill their strongest party, and have your strong units easily handle their weaker ones. (This is what I'm currently doing.)

Maybe have the first and last parties be the strongest. (Like the start and anchor of a relay race?).

Stronger could mean high ATK or high HP. As you can see, there are many ways to arrange the deck. Unfortunately, it depends on opposing raid deck, which you have no way of seeing beforehand. Make your own judgment based on your units. I actually stuck with the auto-built deck until level 25 and did fine. Miyuki: I've been using auto-built deck this whole time with no problems and I'm almost level 50. Just pick opponents with a safe margin away from yours. However, this will have greater effect the more parties there are on the deck. I'd suggest starting off with something that works well against auto-build.

Unit Cost
In addition to positioning you may want to think about building the optimal deck with your available deck cost. Each rarity has a different cost, and a unit of higher rarity costs a lot more. For example, a 5* unit costs 16, while a 3* costs 8. If you have enough deck cost to include your strongest units, that's good. But if you have a bunch of 5* and 6* units, you may run out of available cost before you can fill your deck. At that point, trading a 5* for two 3*s may in fact boost your total ATK and HP. It is also beneficial to have more units in the deck. Unless you're super lucky and have awesome cards, ATK/HP optimization constricted by cost should not be a problem. I started to see this at level 30 when had 4 parties in my Raid Deck.

Quest Skills
The skills that activate in-quest can also activate (at most once) in Battle to provide extra effects. For example, rush skills will increase the damage deal by that unit, multi skills will increase the damage dealt by all units on the party, and passive def skills will increase unit(s) HP. I believe the skills have the same activation chance in-quest and in-battle. Here's another reason to awaken your units.

Miscellaneous

 * 1) Other things I'm not aware of.
 * 2) I'm thinking that Element and Type may also have effects in Battle too, but idk.

Win Streak
You get more VP if you're on a win streak. Each win increases the amount of VP you get by 10%, up to an extra 100% (double) at 10 wins. This is a huge factor, pun intended. Make sure you don't lose! Otherwise, losing only hurts your record and pride. This also means that it may be even harder trying to rank well in a bracket when coming in late. Or that it might not be worth it to try ranking really well in the 5-hour brackets when you can only beat an 100VP opponent. (There are people upwards of 400VP).

Charge
Starting a battle only costs one BP. However, you may choose to spend 3 BP instead to deal 1.5x damage during the Battle. I have not done this as I believe it's risky, and not profitable. You run the risk of losing in every battle, and choosing to Charge suggests you're trying to take a deck that has obviously better stats and maybe more parties. The risks only increase.

If I may make some conjectures: Assume that 1.5x damage increases the strength of the team you can beat by the same amount, translating to a 1.5x increase in potential VP. This means Charge uses 3 BP to earn 1.5x VP, while three normal battles will earn 3x VP. Don't see it paying off in any scenario. If someone can prove otherwise, please do.

BP Potions
Maybe you just need a little boost near the end of the bracket. If you have them, and feel like using them, go ahead. That said, I wouldn't buy them from the shop at 100 crowns a pop. However, if that BP potion guarantees that you rank high enough to receive the gold summons reward, it's up to you. A gold summons is equivalent to 300 crowns if you buy them one at a time. Limited time event summons are where there crowns' at.

Other tips/things
(ex. Best reward goes to top 20 players, instead of top 10.)
 * A bunch of good information can be found under Menu>Help, although it isn't entirely comprehensive.
 * Don't sell your units in general. I haven't had any money problems. Feed extras to others.
 * Don't just look at a deck's VP and ATK/HP. You should also look at the level of the player. A few times I accidentally picked into decks of higher level with more parties than mine had. Although the units were weaker than mine individually, it won in numbers. To be safe, assume quantity > quality.
 * Some limited events (like Halloween right now) is giving 11 gold summons with 2x rates 5 and 6 rarity units for 3000 crowns. Using crowns to buy BP potions is probably not be worth. Should save the crowns for these events. (PAD godfest, anyone?)
 * Brackets lasting longer have more lenient rank to reward payout, but more people participate.
 * Battles also give unit loyalty!

In the end, ranking in a Battles is commitment that may last hours. However, one BP regenerates every 10 minutes, so you'd only have to check in around every hour for full BP, if you're not actively questing/leveling/using BP potions. This method of Battles should easily rank you high enough to at least net a silver summons.

I'm currently level 33, and have finished all available quests.

My current Quest Deck

My current Raid Deck

For my noteworthy rare summons, I have gotten one 6, one 5, three 4's, and over ten 3's. Along the way I have collected 80/312 units. These summons are not solely from Battles though, but it certainly helped a lot. I haven't been playing long, and I'm not that high level, but I believe this will help. Questions/comments/improvements welcome.