I learned how to use FOIL :

F-First term in each bracket

O- Outside terms

I- Inside terms

L- Last term in each bracket

You apply it when you multiply two binomials. Example:

 First you multiply the first terms of each bracket. (x()x) 

Then you multiply the outside term with the first term in the first bracket. (x)(2) 

Then you multiply the inside term from the first bracket with first term in the second bracket. (2)(x) 

Then you multiply the last term in each bracket. (2)(2)=4

The last step is to add like terns and to simplify.

 

=

Some challenges are getting the order confused.