The world isn't really a build-a-girlfriend workshop. The reality is that she's going to be flawed. You're going to be flawed. Your flaws will clash with each other eventually and you're each going to have to figure out ways to grow as a person or move past them.
The biggest things you need to work on with regards to meaningful relationships is to answer the following questions:
1) Respect. Do you respect yourself? Are you willing to defend your words and your actions or are you going to run away from conflict? Do you stand by your principles or do you do whatever is most convenient?
Do you respect others? Do you listen to them without judgment? Do you respect their boundaries and treat them as equals?
2) Communication. How honest are you when you talk to someone? How easy is it for you to understand others emotions? Can you maintain composure and empathy when talking about difficult subjects? Do you ask follow up questions to carry on the conversation? Do you know when to stop talking?
3) Trust. Do you follow through on the things you say you will do? Do you do the right thing without being asked to? Can you avoid touchy subjects? Can you avoid giving unsolicited advice? Do you stick around when they're feeling sad, angry, or upset? How predictable are your moods? Are you willing to share your private struggles with someone else?
When it comes to bettering yourself, really the most important thing is that you should want to become the type of person that you would want to be around
