From ArchWiki

A potential TU should:

Ideally:

• have successfully maintained a selection of pkgs in the AUR or a personal repo for a substantial period
• be a member of the aur-general mailing list
• have good working knowledge of bash, patch and sed
• be familiar with cvs and svn

At least:

• be well regarded by the wider Arch community (i.e. not be an ass)
• be familiar with PKGBUILDing and the Arch packaging guidelines/standards
• be prepared to help other Arch users to improve their PKGBUILDing techniques
• be prepared to take an active part in discussion on the aur-general mailing list
• be prepared to commit time to take part in TU voting procedures
• have been using Arch for three months and be prepared to stay six months in the TU position