Banks exist in every city.
Invis is what you are every waking moment unless there is a specific reason to be visible.
Avoid fighting warriors, but you can pick on anyone else at 17. Warriors are also manageable, but probabnly not for yuou unless they are hurt.
Make an alias fam murder $target and start with it, immediately followed by your alias for c magic $target. If your familiar cannot tank any, reverse the two commands.
Learn about the world staying in your guild by using familiar.
Don't fret about con, this is your learning char. Treat it as temp, let it condie. Your second will be much stronger.
Stay at 17 trying to pk, then stay at 27. Might not want to bother going to 35 if low on con at 27 with this char. Much more important to learn to pk with demon/angel than with devil/archon, which is comparatively easy mode.