MSKLAR has it right, get some lessons, get the basics, group lessons are really good.
If you don't get lessons, then get a good book - Ben Hogans, Sam Snead, Dick Farley and Harry Obitz Seven Days To Better Golf and The Swings The Thing. Dick and Harry advise the seven iron, as you can hit all kinds of shots with it, without getting all tied up.
Watch good players practice (not just the end result of where the ball lands), the posture, care and attention, balance and effortless timing that send the ball a long way wit not a lot of effort.
I go to the range about four times a week and hit three hundred balls a time (a hundred of those are with the wedges). This last point shows that like anything else in life, you improve by practice, particularly if you know what you want to achieve and are willing to devote time to that end.