I think part of the problem is you switch class a lot. Pick something, one class, one build, one weapon and learn to play with that until you stop being bad with it. Just practice and learn from mistakes. If you die you should be able to pin point what you could have done better and do it next time. Don't be too hardcore with practising. The more you enjoy it, the more you play, the better you will get. I think its probably unreasonable to expect to be more than just competent at this game now. People have years of a headstart on you, and even they are still improving
Go on duel for practicing 1v1 and blocking, but don't think you have to get good at that. I'd say you can actually be fairly bad at 1v1 and still do quite well on battle if you learn to team play, and that is something you will get just from playing battle and knowing when to push, when to retreat, when you're strong when you're weak etc. Getting in a clan might help with team play and you might get someone to tell you were you're going wrong