I will chime in here. Most ranges I have been to rent guns. Take advantage, shoot as many as you can. Go to gun shows, get as many different guns in your hand to find out what feels right. When you find a gun that feels good in your hand, see if you can rent a similar model and shoot it. Try out different calibres. I recommend going with the largest calibre you are comfortable with, if it is a .45, great, 9mm, fine. If all you can handle is a .22, a well placed .22 is much better than a miss with a .45. Find out what works for you.
Based on the question, I would also guess you are not very experienced with firearms (if you are, great!!), take more classes (even if we are experience, more training never hurts). Also, shoot often, until you do not have to think about what you are doing when you are shooting. I always say 100 repititions, your mind knows what you are doing, 1000, your body knows what you are doing, 10,000 your spirit knows what you are doing and the technique becomes useful!!
Good luck and enjoy!!!