Wash and dice your onions and tomatoes and set them aside.
Cut your avocados in half length wise and remove the seeds. I find it easiest to stab the seed with a knife and gently pull the seed out.
Using a spoon scoop the insides from all of the avocados into a large bowl.
Once all of the avocados are scooped out use a potato masher and smash all of the avocado. You can make is as smooth or as chunky as you would like to. I personally like to have chunks in my guacamole.
Add the lime juice, garlic powder and chili powder to your avocado and mix well.
Then add in the diced onions and tomato and gently stir to incorporate into the guacamole.