Defiantly go to a bow shop and have them fit you and teach you proper form. Any archery shop that I know of will gladly spend the time to teach you proper form and give you all the advice you can take. Also, don't pick a bow the first trip in, try them all several times. Plus, once you figure out your measurements, don't be afraid to check ebay and used online sources to save money.
Also, if you can't draw back 40 lbs the first time you try, don't give it up! The first time I picked my bow up it took me 4 tries to finally pull it back, but after I finally got it back, I could pull it back all day long with no problems. Some of it is just not understanding how the muscles are supposed to pull it back. However, if you consistently still have problems pulling it back, don't be embarrassed to have to start with a lower weight. It is better to learn the proper form at a lower draw weight, your accuracy and form will feel much better, increasing your comfort and ability with a bow.
My last piece of advice is... Once you get somewhat comfortable with your bow start to practice at longer ranges. I like to practice at 50 yards and can consistently hit pretty decent at those ranges. In a hunting situation however, I don't feel comfortable over 30 yards so as not to risk a animal jump or poor shot. Practicing at long ranges however forces you to perfect your form and concentration. Making the short shots much easier and natural. Practice everyday if possible.