K.I.
With my first I only put milk in the sippy cup and went straight from bottle to sippy...and it was easy!
With my 2nd child, he wanted nothing to do with the sippy, and I had to trick him...I always use flavored coffee creamer in my coffee and one day I was trying to hand him his sippy of milk and make my coffee and he wouldn't take it, so I asked if he wanted some creamer like mommy and he was all excited! I pretended to pour some in with his milk and he loved it! He totally thought he was getting something special...but he wasn't getting anything but regular milk ;) it was hilarious! It worked for us, but was slightly annoying having to pretend to put creamer in it every time...but it worked!
I was lucky with my 3rd...she loved her sippy from the start, even if it was only water!
All 3 of my kids transitioned to the kind with the straws really easily, they liked the straw!