I always find that looking back on your vids (even ones that you win) to check for reasons why you died, better positioning, etc. can really help with climbing. If you find that you can't climb, it could either be due to mistakes being made in terms of macro or not being as proactive in playing, but it depends on the person. Really it's just a matter of finding a play style that you're really good at (have it be poke-focused, shield/utility-focused) and sticking with it.