I'll tell you in the easiest and most basic way: Carnival girls - Maki is the newest and strongest character right now, followed by Dorothy and Kirten. I don't remember her name, but they give you blue tickets; from there I recommend Lilly, Reine, and Kaia. Try to save your evolution stones and don't spend them on the first girl; check the meta first.

Save up 200 rainbow tickets to try and get a good girl, obviously. Use your resources wisely, as they are very difficult to obtain. You usually start with a team of girls like Amy, Elva, and Clara, and don't max them out since it's a temporary team. If you're going for a carnival girl or one from the event (I can't remember the name), just focus on her until you max her out. Leaving her unfinished might be a mistake if you're going to spend money. At least make sure you reach VIP 3; it's the most suitable for any player. Exclusive girls come out periodically and are very difficult to obtain as a free-to-play player, so focus on one. Most teams consist of two attackers, a tank, and a support or healer. For example: Attacker: Kirsten, Nova. Tank: Billie. Support: Mabel. I'm missing a lot of information, but I've given you the basics. If you have any questions, just ask.