The best things you can do to make your project as good as it can be:

It’s about the song and the performance.

          Rehearse the songs so you’re ready to record -- Writing in the studio is cool,
          and sometimes you'll get some great stuff. It also takes a lot of time while
          the meter is running. So unless the plan is to write in the studio, you'll get
          more done and have more fun if the stuff is rehearsed.

          Record the songs yourself — using anything you can get your hands on
          and listen back. You’ll hear the song differently when you’re listening back.

Get the gear in shape.
Have the guitars professionally set up. It’s cheap and makes a big difference.
Get new heads on the drums. Not as cheap, but makes a huge difference in your recording.
Check out the amps and effects. If there’s anything wrong it becomes much more apparent in the studio.
Use gear you’re familiar with, or you’ll be spending studio time figuring out new gear.

References tracks are a big help
Have a list of some songs that you know and love to reference in the studio. It will help your engineer get what you’re looking for. It also helps you get tuned in to the sound of the studio.

Who’s producing the project. 
Most independent projects are self-produced. Even if the project is going to be co-produced by band members, there should be one person in charge to make the decisions in the studio. Too many cooks...

Closed sessions will get the best results.
Guests in the studio may seem like a fun thing but will only distract musicians and engineers. Plan other listening sessions either at the studio, or in rehearsal spaces to include other people if you want to keep them involved. It's hard to pay close attention in a busy control room. You'll find stuff later and wonder how the heck that got by you. 

Weird sudio things that matter ~ if you ask me: 

Click or No Click:
          A click track is awesome. A click track is evil. There is a right answer. It depends.
          One thing I know for sure is that unless the songs are well rehearsed to a click,
          then don't record 'em to a click.
          Record the songs the way you've rehearsed the songs.

          Headohones are evil. Headphones are necessary. Almost all recording sessions
          require monitoring in the 'phones. It's a skill and it takes getting used to.

Dress for Sucess: 
          Wear comfortable clothes, and materials that won't make noises when you move.
          Big zippers and buttons and most jewelry can make sounds that get picked up by
          the mics. Consider your hair, too, bacause you'll most likely be putting on
          headphones and you'll want those to fit properly.

Close Quarters:
          Keep in mind that even in big studios you'll be working closely with other people.
          And most control rooms aren't that big. Avoid perfume and cologne.

Thought For Food:
          Plan the food situation especially for longer sessions. And even for shorter ones.
          If you're going to eat in the studio you'll want to plan on stuff that isn't too messy.