First, you may not know a very interesting fact about your Gmail email address : you can use your regular email address as email@example.com and also firstname.lastname@example.org.
Second, it is possible to append a plus sign (“+”) followed by any text to your Gmail user name and hence create as many email addresses as you want (e.g. email@example.com redirects to firstname.lastname@example.org). However, many websites do not allow the usage of the plus sign in your email address and this trick is easily recognized by email spammers.
A better solution is to remember that full stops (“.”) are not considered by Gmail (e.g. email@example.com redirects to firstname.lastname@example.org as well as email@example.com), so you can use them to properly filter incoming emails (e.g. use firstname.lastname@example.org when registering to websites and then filter those messages).