I recall a thread about this subject not too long ago on this board (sorry - don't have the time to seek it now) about deep throating and although most men claimed they wouldn't mind a woman doing it more said it was of no importance and one answer saying he didn't like it .. and from what I remember quite a few Ladies said they couldn't do it because of the gagging, while those who could just stated they could and never did anything to "practice" ...so maybe this is why there weren't any suggestions as how to improve your skills.
I for one think it doesn't really matter all that much - the "best bit" is in the nibbling - licking - playing - sucking the head and balls - making sloppy noises for some *winks* - just the "act" itself and the dedication and passion with whitch you do it, and not so much how much length you can take down your throat...
sorry - not that elaborate an answer but as I said - in a real hurry atm.
Yes this thread was done before so looking back may give you some tips. All I have to offer is do it in a totally realxed state. If you don't relax your throat muscles you will be sure to gag. And also remember some people just can't do it their gag reflex is too pronounced.