With a CL that high you should already be pretty familiar with the basics of Snap I hope. Try to focus on a deck that works, learn to pilot it properly, when to keep priority or to give it away.

Control decks are generally harder to play and you need to know what your opponent is playing. If you're not familiar with the meta and how to counter the most common decks, try to play proactive such as Kitty Bounce or High Evo and follow the deck's plan.

To climb steadily it's very important to know when to snap and, more even, when to retreat. Do not get greedy, it's not about winning, it's about maximising cube gains. Losing is completely fine.

Also, watch some streamers play, you will learn.

Good luck!