Thanks for the compliment, and I'm always happy to help!
The first step in this transformation is that you need to change the goal. Changing who you are just to attract "the right guy" is short-sighted and also a bit unfair to you. If you're making a change, make it for you. You should want to cast off the trappings of an "irresponsible party girl" because you're ready to move on, grow up, and set long term life goals. Look at finding a good man as an important, but secondary, goal.
Now that this is all about you instead of all about an as-yet undiscovered boyfriend, the second step is to set very clear goals for yourself. Be specific and be honest. What bad habits do you want to target? What new and good habits do you want to implement? Write them down and assess how feasible they all are. And then, once you do that, make the promise with yourself to do what you've set out to do.
The last step is to track your progress. If your goals are "to make new, mature friends," "join a team" and "begin a healthy hobby for when you're by yourself," then actually write down what efforts you're putting in towards each of them. Don't hesitate or exaggerate. Just as you were honest in setting your goals, you need to be honest in tracking them.
You'll notice that I didn't add in any tips or hints about where to meet guys or how to change your image around guys. Those things are going to come in time, so long as you focus on yourself and the life changes you want to make.
In short, your focus should be on you. If you focus on you, the right guy will focus on you too.