relatively simple strategy:
start lily white, plop down an aki relatively quickly, get nazrin up to 5* asap and then pump out good, high damage 5*
good 5* options for your first deck:
rumia (press R to awaken her, only get one)
reimu
cirno + daiyousei + letty whiterock combo
remember, pure damage cards are better on their own but magical (cirno, letty) do just as good if you have magic resist reduction (like letty) [this also applies to physical cards but I don't think you get any good physical cards or armor reduction cards to start with]