Personally, I dont like drinking alcohol with E - its ruins the high because its a depressant, and E is an upper - why mix the two?
Also, dont drink too much or too little water - just sip water every so often and keep cool.
1 pill will be ok for your first time, but make sure its coming from someone you trust, and preferably someone who has already tried them.
Its a very controllable drug - you will walk and talk the same as normal, its mostly your mood/mindset that changes - from doing just ok, to feeling incredibly euphoric, on top of the world - sooo happy and you cant wipe the smile off your face.
5 things you must do on E

1)Smoke a joint
2)Listen to music
3)Go clubbing/to a rave
4)Go a walk outside
5)Hug someone/receive a massage.

If you get a good E, you are more or less guaranteed to like it. And it depends on your personality type but E is far better than coke, longer lasting and cheaper