1. Have a good/decent website.
2. Recruit fast and friendly members who aren't dickheads and who will make your clan look respectful therefore more players of this skill will want to join.
3. Run a server/s with good tracks (popular TM2 tracks) and up-to date plugins (i.e XASECO, MLEEP).
4. Make sure you are active on the website and your servers in TM.
There is proberly more but that's all i can think of right now
- Kama