Using a whisk or fork, gently mash up the avocados (making sure to leave so decent chunks. unless you aren't into that...) the squeeze in the juice. Add the sour cream and the cilantro (can also use milk. I learned this from Patrick Singly - the owner of Gautreau's, father of the chirren I'm babysitting tonight and superhero that fixed my flat tire which I got on my way to babysitting last week. he says it helps keep the guacamole from turning that gross brown color). Then add the salt and lastly the diced tomatoes.
Recipe by A Sue Chef at http://www.asuechef.com/easy-guacamole/