Any tips for Shen?

What exactly do you want to know? I have a good amount of shen experience.

Vs teemo just try and farm and build some early mr and wait until you are tanky enough to fight him, In a general lane vs an AD champ always rush sunfire, against AP go some kind of full MR item. I always grabbed a Titantic Hydra as my 2nd item and then built full tank. Don't be afraid to fight because if you hit your q on someone you will win the trade 99% of the time if you use your w to block their attacks and e to dash out.

The only thing i know (not a Shen player) is that having the sword travel through an enemy when recalled will make your enhanced autos do more damage to the target it passed through.

Ya either way the Q does more damage but if it goes through a champion they move 50% slower if they are moving away from you and he bonus damage is doubled.

Your w can block fiora proccing her passive.

Shen isn't a bad laner but don't forget your base stats are absolute garbage.