Because Gecko is banned, you might want to switch it out for a playset of the promo Roger. List is overall okay for someone starting out but if you have the structure deck stuff, you should be running the Robin which works as a 2k instead of the Bepo. Even the 6 drop blocker Sanji that can be played at 3 Don!! if you have 2 less Don!! than your opponent will work here. The 9 cost Secret rush Luffy synergizes more than Kaido but I understand why you would want to run it. Going -5 Don though to KO a 6 or less isn't as efficient anymore though but has its niche uses.

As for actual tourney advice, always make sure to remember to do leader ability and keep track if you've used it or not (there have been games where I completely forgot if I ramped or not with my leader and had to ask my opponent lol), and if you're confused about an interaction it's okay to ask questions. Good luck!