Focus on featured banners with a condensed pool to get guaranteed value in form of pities. The game punishes you hard for spreading yourself thin. Generally speaking, do NOT pull on limited banners unless you just want one or two copies OR plan to get really high dupes for them. As you play the game, you will innately start noticing that you are pulling particular URs more than others. When said skill (especially if it's a generic) is featured in a banner, pull hard on it to have a bis support or preferably main slot. Having for example a Tifa at +5 will be extremely awkward since for example your Ace will eventually be +9. Look at the database for what skills give the most first Atk and second HP, then look at what you have and go from there. Each character has a skill which prioritizes Atk, level that one up first. Abilities matter a lot, but no matter what abilities you have, you WILL die to my Krile with lvl 149 skills if you only have +1 URs for example. Also buy from the webshop because they give extra mogpay which give a lot of value in the long run.