Spotting knockoff brand clothing or accessories is a skill that anyone who wants to get their money's worth should have. However, if you don't know what to look for then you won't be able to tell the brand names from the fakes. Concerning products made by Burberry, there are some definite things to look for in order to confirm that what you're buying is the genuine article.
Look at the plaid. Burberry products have a distinct, symmetrical plaid pattern on them. There should be three, thick navy stripes crosshatching each other. There will be thin, red stripes that cross exactly in the center of the blue strips, not the crosshatching. If this plaid pattern is off (most especially with handbags) then it isn't a genuine Burberry.
Look at the buttons. All Burberry buttons have a rat-tail on the end of the R that curves up slightly. If the end of the R is flat, then the product is probably a knockoff.
Examine the logo of the knight on his horse. A genuine Burberry logo will be sharply defined so that the horse and the knight riding him can be easily made out. If the logo is blotchy or misshapen, chances are it's a fake.
Examine the hang tag. A genuine Burberry tag is made with string, and it cannot be pulled off without damaging the garment. You should have to cut the string in order to remove the tag.