don't beat yourself up. it takes at least 5 details to have a grasp on detailing, another 10-15 to feel competent, and many many more to master it. its gonna take a good 10-15hours of using the DA to feel really comfortable and get good results. few people get professional results the first time. watch mikes videos and try again. in time you will be able to detail quicker, expect the first five or so to take some 15hours per car.
[ame=http://www.youtube.com/watch?v=Q70g83mnTn4]How to do a "Section Pass" with a Porter Cable 7424XP - YouTube[/video]
Sometimes after claying you need to wash the car all over again. I prefer ONR. the other option is to do an IPA wipe down. rubbing alcohol and water(i use 1:1 or you can dilute it more. neglected paint always takes forever to clay. expect 20-60mins, maybe more. remember use lots of lube, light pressure, and very fast passes, up down, left and right.
with a DA work in small sections 12"x12" do a test spot. always always do a test spot. try different pads, different products, different amount of preasure and different number of passes. I have a groit DA, most daily drivers i do need m105/meg ultimate compound with orange pad speed 5 with 4-6passes. the follow up with white lake country pad with m105/ultimate polish. i like hydro pads and surbuff pads. i do a few small sections, determined what works best and then do the whole car. nothing is worst than doing the whole car, then checking results and being disappointed. you need more passes for sure, compound won't even start to break down till 4 passes.
on your backing plate use a sharpie and mark it. sometimes if you use to much pressure it bogs the machine down and the pads won't spin. so make thick line so you can see it spinning with a black sharpie.
i love collnite 845, wonderful wax.