I strongly recommend joining the 1v1 ladder and/or the seasonal ladder once you join the 50 club. These pure skill 1v1s are great to learn from. You can then watch the replays of those, and even better ask the other player what they did to beat if you conceed defeat.
Another helpful thing is to have others evaluate your games. That clan you are in will most likely have friendly players to help you get a 2nd opinion on your game style.
Watch replays of games by high level players. Analyzing their strategies can give you new insight.
Lastly, play lots of games, especially at high levels! PLay real time games to help follow your own stategies and get quicker feedback on what worked and what didn't. I often play fun, 1v1 short games using templates such as
https://www.warlight.net/MultiPlayer?TemplateID=555166 . Don't be afraid to take on games against tough opponents, as novice players will not help to boost your game.
feel free to shoot me a game invite!