Whether you're auditioning from a P2P audition site, through your agent or just a random VO buyer who wants to hear a few reads before they hire you, it's vital to think out of the box and give yourself the best chance to book the gig.
When looking at the script, study the message and pay attention to who the target audience is. This will make a difference in how the script should be performed. For example, if it's a commercial aimed at teenagers, your performance will sound quite different than if the campaign is aimed at adults 45 and up.
With P2P sites, talents tend to rush on the audition due to the hundreds of other talents reading for the same gig. In fact, most glance at the instructions, record and submit. I would advise you not to do this. I know you want to get the audition in quickly but you also want your performance to stand out.
Slate your name and then record three versions of the script. Stick to the instructions on the script but make each take sound a little different. Maybe one take is a little more cheerful than the next take. Perhaps one version is punched a little harder than the rest. This gives the client more to think about and they're going to love that you chose to overdeliver for them when you haven't even booked the gig yet. You're also putting yourself ahead of others auditioning by offering the client three different reads.
Labeling the file is very important no matter who you are auditioning for. Please pay attention to the client's instructions on how they want the file labeled and never send it in not labeled. It may never get listened to if you don't follow specific protocols. Talent agents are especially strict with this rule.
Make sure your audio is clean. No room noise, dogs barking outside or air conditioners! You never want to send in a noisy recording. The client will assume this is how the booked VO will sound, so they will skip you and move on to the next talent. Recording auditions via a USB mic in a large, noisy room will not cut it; if you don't have a decent space to record, work on it before you start auditioning.
There is never any reason to follow up after an audition. Agents and clients have plenty of talents to listen to and don't want to be bothered with many emails or phone calls. This is generally the rule of law with talent agents. Pros don't follow up. They record, submit and forget. If you book the job, you will be the first to know!