Improving my bike... where to start

[TheDoctor]

Tyres and wheels, like everyone else has said.
Handbuilt Open Pros and Conti Gatorskins will transform the feel of the bike. They're easily strong enough for commuting. You'll not get much change from £200, but it'll be well worth it.

 

[alp1950]

Upgrade your engine.

Keep riding, and when you think you're pretty fit & reasonably fast join a club. You'll then discover just how much faster you can go if you really push yourself. Even then you'll find that you will be blown away by some of the more experienced riders- but at least you'll know how much better you could get.

Over the past year bought a new bike, went clipless & worked on cadence. These all helped improve speed- but having realised these gains the next big improvement came from joining a club. Within 2 weeks of joining I've manged to knock 10% off my commute time & increased average speeds by about 2 mph.

(Bike upgrade? - nearly forgot- we did put some nice new red bar tape on).