Want to do~ ～たい

First get the ～ます masu form of the verb you want to do.  Then drop the ～ます masu and add ～たい tai. 

たべます tabemasu (to eat) Arrow image たべ　tabe Arrow image たべたい tabetai (want to eat)
のみます nomimasu (to drink) Arrow image のみ　nomi Arrow image のみたい nomitai (want