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