Here's an easy and fun way to improve your game.
If you're like me, you have a good natured rivalry with your gaming buddies.
It's fun to keep a tally of your wins and losses against one another and to create narratives about the glorious, or sometimes inglorious, histories between your respective armies.
A really cool wayto mix it up is to swap armies for a game and play your friend's army and he or she to play yours. This gives both the opportunity to get an intimate feel for how another army and list plays which will help you to better understand it's strengths and weaknesses. It also allows you to have the opportunity to see someone else play your list, which can bring to light entirely new strategies and ways to play it you had not considered.
It also let's you see your army's strengths and weaknesses as viewed from the other side of the table. This also settles any debates about one or the other player's list being cheesy, as if you can win with your ad!y and then beat your opponent with his or her army against yours, you can end that debate quickly.
So try army swapping out! It's fun, easy to do, and will improve your game. Just be sure to wash your hands prior to touching someone's army and to treat their models with respect.