most errors are when spraying. yall should press the spray nozzle head maximum 1 second and let go. move in a left and right motion while pressing the nozzle and when an area is covered, move over to cover whole area. 2nd and 3rd coat, do the same if u wish to do so. then comes the clearcoat using the same technique. this way u dont get too much spray bleeding down and damaging the overall look.
u can buy the same color as ur car color through some hardware shop but small tin and expensive price, around rm15-18. i suggest u find a "steel paint" shop and ask for ur car color code and they will give it to u in the normal tin size (rm20-23)....
while ur there, get a rubber/foam waterproof sanding block for your sanding purposes. and the correct version of sanding paper is not those u get in a hardware shop but here. which is, 'kovac' eagle brand waterproof abrasive paper P80 for initial sanding and P320 for more fine sanding...
u can get the autocolor cement from a hardware shop. the real process is actually red color cement than yellowish-gray color cement (the steel paint shop mustve got this as well) and lastly "autocolor hard putty" for final coat.
when cementing, if say u doing ur mudguard, theres a lining usually on the metal (curves of the car/top half of the mudguard), if ur dents are below that curve, cover that up and cement the whole of the bottom half of the mudguard. this way, after sanding, u get the overall clean shave instead of tompok-tompok due to cover only the dents.
hmm... good luck!
:P