VfrPilot, the other way is to work out the common a/c being pointed out (probably C152/172 and PA's) and unfortunately teach yourself what they look like. Get the defining characteristics so you know them. Then if an a/c is called that you don't know, ask ATC for more specifics, and try to compare to the manufactors' other models that you do know. Gradually you'll get better, and if still unsure, ask ATC 'is that our one' as the a/c passes, always best to be SAFE......
A/c recognition is a big thing during the initial courses at the NATS college, and having spent many a day at an airport trying to get collegues up to scratch, know how tiresome it can be, but if it helps safety, it must be worth it.