July - October
Rolling admissions is best taken advantage of early on in the admissions process -- ultimately, rolling admissions is a type of admissions that stands alongside early admissions and early decision. If there are schools you're confident that you want to apply to at this stage of the game, and they have rolling admissions, then you should be completing your applications as early as possible and sending them in.
You'll want to make sure with those schools exactly what their opening dates or deadlines for application submissions may be. Some schools with rolling admissions will accept applications at nearly any point of the year, but others will still have specific windows during which they will want potential students to send in their applications. You should make sure of which the schools you're applying to may be, so that you don't send in your applications too too early, and get them ignored or sent back.
When you're doing your applications for rolling admissions schools early in the process, you should be attending to them with the same care and focus as you would any other application, if not more care. Sending in an application to a rolling admissions school early can give you a leg-up, but it won't make up for sloppiness on the application.
If you get in your application early, you may hear back just as early from the school. In that case, you'll either find out that you've been waitlisted for the time being, denied, or accepted. If you've been accepted, then you'll need to find out when the school wants a response to the acceptance, and plan accordingly.
November - January
If you're applying to a school with rolling admissions around this time, then it's important that you take the process seriously. At this point in the applications process, you're likely going to be applying in direct competition with many other students applying for rolling admissions. Your application will still be judged as soon as it is received, but because there are other students applying, the admissions officers will be able to look at your application in contrast to those of the other applicants.
It's important to treat your rolling admissions application with as much seriousness or focus as you do any of the other applications you might be filling out at this point. It's still much better to get your application in sooner rather than later, so the earlier you can finish off your application, the better.
Don't forget your other applications, though, while you're doing any work for the rolling admissions schools. It's important to be applying to a number of potential schools, especially at this stage of the game.
Otherwise, keep in mind that you're nearing the stage where you should be looking into financial aid and scholarships. Almost as soon as you hear back from the rolling admissions school on whether or not you've been accepted, you should start trying to communicate with them about whether or not they have any financial aid for you.
February - April
If you're applying with rolling admissions at this stage of the game, then you need to be working calmly, clearly, carefully, and quickly. Rolling admissions works on a "first come first served" basis, and at this point you're likely one of the latecomers. That doesn't mean there's no food left at the table, though! You just want to make certain that you aren't any later than you absolutely have to be.
Take the care you need to make sure your applications are still filled out correctly and competently, but make sure to get them in sooner, rather than later.
Also, you can't wait to hear back from schools before you start working on financial aid. You need to make sure that at the same time that you're sending out these rolling admissions applications, you're also communicating with schools about possible financial aid, and you're pursuing as many school-independent scholarship opportunities as you can. If you wait until you hear back from these schools, you'll likely be too late.
Before you put in the effort to apply to a rolling admissions school, make absolutely certain that it doesn't have a deadline. Plenty of rolling admissions schools keep accepting applications until all the slots in the new class are filled, but some do have cutoff dates, past which they will no longer accept applications. Make sure you're not wasting any time working on an application for a school whose deadline is already up.
You'll also want to apply to a wide array of rolling admissions schools at this point in the game. Since any given school might be full up on students, the more schools you apply to, the greater chance you'll have of getting in. That said, there's no point in applying to schools that you would never go to. You'll need to be making decisions about what the most important things you want from a school are, so that you'll be able to decide if you would even go to those schools if you got in.