I agree with most of the other posters.
The only way to get better is to learn from your mistakes, to understand why your tactics succeed or fail. The best way to do that is to make a lot of mistakes, and the fastest way to make a lot of mistakes is to play someone better than you. Playing someone better than you makes it plainly evident which of your normal tactics do not work as well as you might think. It forces you to pay attention to everything that happens, to think about why you failed, and to come up with other things you might have done instead.
I would play your friend. When I was trying to step up to a competitive level in Melee for the first time, I was only able to get so much experience on my own. And while I've been to few tournaments still, the best thing I did to get better was attend a tournament and get my *** handed to me by players who were downright better than me. Losing to them made it plainly obvious what I needed to improve on, and how I should be playing. It forced me to reconsider the way I play and work to improve. And improve I did.
Playing better players is a great way to learn your own weaknesses, but it's up to you to work at correcting those weaknesses. Hope this helped.