Absolutely.
1) Begin with stock paint
2) Use pneumatic or electric DA sander with dry 180 grit pad to rough up existing paint
3) Identify low spots / spots in need of body work
4) Do body work. I popped as many dents as I could, but I had to resort to Bondo and spot filler quite a bit (20-year-old paint, lots of little chips in paint, spot filler works a treat)
5) Wet-sand Bondo flush to body panel with 500 grit
6) Go over panel with tack cloth and make sure it's totally clean. It would be prudent to also use wax&grease remover, but I did not
7) Wet the floor of painting area and sqeegee the excess water out. Let it sit for a bit to let excess moisture escape. This kept humidity down for me and obviously helped combat airborne dust particles
8) Spray your primer. Go for full coverage, at least, but you can keep building up if you need to fill a few really minor flaws (spot filler should have covered most of them)
9) Let primer set up for 1-2 hours (depending on brand) and then wet-sand the primer with 500 grit and get it nice and smooth (See below...you'll want to use the soon-to-be-mentioned sanding blocks for this step)
10) Tack cloth again to remove dust and other junk before you...
11) Spray color.
12a) Now, if you are shooting a single-stage paint, put 3+ layers on. You are going for not only full coverage with the paint, but you want to build it up enough to where you can wet-sand it and buff it afterwards (and for years to come, if needed).
12b) If you are shooting a base coat / clear coat, just get good, even coverage with the color, you may only need two coats of it. As long as you don't have a lot of orange peel you are ok (you will have some...robots at auto manufacturers can't even spray perfectly, look at the paint on a brand new car...). In my experience, if you cake 3 layers of clear on top of the lightly orange-peeled paint, you can wet-sand the clear and get a pretty good looking result. If you are going for a show-car finish, then stop reading this thread and go to auto-body school!
*edit* I Google'd this a lot before starting and most people say that orange peel in the color coat will show through the clear no matter how much you sand the clear...I didn't find that to be the case, and I have a pretty critical eye for my own work. Anyways...on with the show...
13a) Alright. So - you've got your color laid down with a few coats of clear on top of it. You've waited 3-4 days for the clear to set up (I've wet-sanded clear coat after about 18 hours...but, unless you're in a hurry, wait for it to set up and cure a little more)
13b) Get some sanding blocks...
Motor Guard RL-1 Roller Block Sanding Block - Amazon.com
Amazon.com: Motor Guard SB-1 Soft Block Flexible Sanding Block: Home Improvement
Motor Guard HT-1 Holey Terror Sanding Block - Amazon.com
And get a California blade
Pilot Automotive CC-2010 11" Soft and Dry Water Blade : Amazon.com : Automotive
13c) Fill a spray bottle and a 5 gal bucket with lukewarm, soapy water. Just use dish soap. Soak a 2' x 2' or so area and hit it with 1000 or 1500 grit sand paper. Start "cross-blocking" the area with the sandpaper, using the sanding block. Basically, you just want to make your sanding strokes be perpendicular to each other. Usually I go diagonal strokes from bottom-left to top-right, then go back over the area the opposite way. Just google "cross blocking" if you don't get it.
13d) After a few strokes in each direction with the sandpaper, squeegee the area off with the California blade. You'll immediately see that the area is now really, really dull. You'll inevitably see a few spots here and there that are still shiny...those are the low spots - you want to keep sanding lightly until they are gone. Soak the area and sand those spots a little more, a little at a time, squeegee-ing the area frequently until all shiny spots are gone. This is where you'll probably be thinking "What the F am I doing...this looks dull and terrible". It should look like that at this point. Don't worry, dull is exactly what you are going for. Don't burn through to the primer!!! If you do, hit the panel again with 500 grit wetsand and spray more color. It happens if you aren't careful, but it's not the end of the world.
14) Hit the area with 2000 grit, now. If you did a good job on the previous step, you are only using the 2000 grit to remove 1000/1500 grit sanding marks. Again...cross-block in this step.
15) Optional : Use 3000 grit paper to wetsand the area further. Haven't done this enough to know if it's necessary. I used the 3000 in the above picture of the hood.
16a) Use Meguiar's Ultimate Compound (by hand, or get someone to teach you how to use a power buffer). I am a bit gun-shy of my power buffer, as you can easily burn through paint and clear coat on the edges of body panels.
16b) Wet the area and use the remaining Meguiars compound to further work the area. Wipe the area off with a lint-free cloth. You should have a pretty decent finish. I really don't know how long you have to wait before you use polish.
You don't need to use Meguiar's Ultimate, but you should make sure whatever you use is safe on fresh paint. Google it...don't take a chance and F up your new paint. I'm sure someone that does this for a living will tear my process apart...but hey, I'm not a pro.
I'm just an average Joe that does IT work for a living and car work is one of my many interests (I play ice hockey, race R/C cars and slot cars, play and paint Warhammer 40k mini's, paint model military craft and cars, play airsoft, powdercoat stuff...the list goes on and on.) This is how I accomplished the finish in the pictures shown above. You can see in the two pics of the rear left quarter panel that you can end up with a lot of orange peel and still have a good looking product if you're willing to wet-sand and buff your newly-sprayed paint.
Please feel free to ask any questions about any step. I tried to be thorough. There are many guides and videos online showing how to tune an HVLP gun. Those are required reading/watching. And, with the money you are saving my painting your car yourself, you should be able to afford a somewhat decent HVLP gun. I bought a DeVilbiss FLG-4. I found it locally on CraigsList for $175. It's not the end-all be-all, but it is better than Harbor Freight (I have two HF guns - I'd use them for thicker, higher build primer, but that's it)
[ame]http://www.amazon.com/Devilbiss-Finishline-FLG-670-Solvent-Gravity/dp/B006ZO2MI8/ref=sr_1_1?ie=UTF8&qid=1352923132&sr=8-1&keywords=devilbiss+finishline+4[/ame] <-- link to DeVilbiss gun I used
Again, I'd love to help anyone - just keep in mind that I am an absolutely self-taught novice painter that Google'd the ever-loving shit out of this subject, did a lot of asking around, and only a small bit of practice before deciding to shoot my own car. It's not impossible, not even close. I'm turning out paint in my garage that, minus a few dust specs here and there that floated onto the wet paint, look better than most factories would do. I'm waiting to do the engine bay until the next time I pull my engine, for anyone that is wondering.