So you want to learn how to play the acoustic guitar and most likely you want to make as much progress as possible in the least amount of time. It's a fact that if you truly apply yourself you can actually learn to play at least one song in about a week.
Go Easy On Your Fingers
Do your research and pick one of the best acoustic guitars for yourself. Consider making your first guitar that you will be learning on a nylon stringed guitar. It might not have the bright sharp "twang" of a steel stringed guitar but it will sure be soft on the fingers. If you are going to get serious about practicing, the last thing that you need is hashed fingertips from a steel stringed guitar.
Case and Capo
Get a nice case and a capo. Thats the thing that you can clamp on the neck of the guitar. It makes for a much higher and often brighter sound and you will have some fun experimenting with different sounds with it. Also, remember to buy some extra strings and keep them in the guitar case.
Get a Good Guitar Tuner
There are several guitar tuning devices out there to pick from. Some, like a tuning fork can be difficult to use for a beginner that has to rely on their ear with this type of tuning device. The best are electric guitar tuners that have a screen that allows you to visually tune your guitar by displaying the sound wave on a screen.
Learn With a Friend
Another good bit of advice is to reach out to more then on source for your learning material. There are great instructional DVDs and software that is now available but that shouldn't be your only learning source. Consider taking private lessons from time to time to augment your material that you purchased online. Also, it sure does help if you have friend that you can learn and play guitars with.