... says:
20 What advice would you give to someone who just starting out with track building?
The best advice i can give to starting builders: build tracks you yourself like to drive.

Apart from that another good tip about making a name for yourself: use the TMX Beta area to upload your 1st few tracks.
The track still gets a number you can use to add it to servers, so people can try out what you've come up with. Then ask for comments on the track once it's on a server.
Hear them out, negative feedback still is feedback. Learn what others want in a track and alter your track if necessary. Once it's fully done, press Release.
This way your buddies can drive your tracks and those who don't know you yet will get to see the finished tracks only instead of a collection of possible bad tracks.
(which results in people returning to your profile page to see if you've built more)