1. Ensure you have a good fit.
2. Ride more.
3. Ride with people faster than you.
4. Ride more.
5. Focus on the engine (you) not the bike. Buy upgrades if you can afford it, but the engine is what you need to focus on.
6. Ride more.
7. Establish some structured training to your riding and incorporate recovery rides (those are easy days).
8. Ride more.
9. Take care of your bike and develop a structured maintenance/cleaning regimen. A clean and well maintained bike is a fast bike.
10. Ride more.
11. Have fun, because if your not having fun, you're not going to want to do it. Set a goal, start of with a C group (about your speed). Learn how to ride in a group, enjoy the comradery. Move to a B group and challenge yourself. Hang on for as long as you can and the next time try to hang on longer. Before you know it you will be finishing the ride with them. Move to A group and repeat.
12. Ride more.
You do this and you will see the improvements fast. How do I know? Because I've done it. I was exactly where you were at your speed when I started. Those improvements will motivate you to train harder and ride more, making you even faster.