If you have trouble remembering your number plate number when filling out registration forms or taking your car to the mechanic, you might be able to improve your memory using mnemonic devices -- tricks to help you remember numbers better. This might not help you if you witness a car speeding away after an accident, but at least you will be able to remember your own number plate under normal circumstances.
Break your number plate number into three parts. Many states require number plate numbers to have seven digits or letters, so you can break the tag number up into two groups of two characters each and one group of three. For example, if your number plate number is MLR7568, you can break it up into ML | R7 | 568 in your head. It is easier to remember small units than to try to remember an entire letter/number combination at once, according to creditcards.com.
Make an association between each small unit and something familiar to you. For example, perhaps you could think of the letters "ML" as your cousin's initials or the initials of a famous person you admire. For letter/number combinations such as "R7", make a question or statement out of the combination. For example, if you know seven people whose names start with R, you might make a mental picture of all seven people inside your car. For number combinations, think of a way the number might mean something to you. For example, "568" could become "five people born in 1968."
Say the number aloud using your associations so that you get the order of the units into your memory. For example, you might say, "Martin Luther Ronnie's seven, five born in 68." Set a timer for one hour and then repeat your associations aloud.
Test yourself by attempting to say the number aloud without looking at it. If you cannot remember the number, repeat step 3 once an hour until you can.