Guacamole:
3 avacados (ripe)
3 limes (juicy)
1 Jalepeno (red)
1 tablespoon salt (Kosher)
1/2 red onion (purple onion)

How to tell if an avacado is ripe:
If you bought hard avacados, you'll have to squeeze them every day to see if they're ripe. When you feel just a little bit of give, they're perfect. If they feel mushy, they're probably all brown and nasty. Its better to buy hard avacados and wait a few days. 
How to peel and pit an avacado:
Cut in half with a chef's knife (vertically, so you end up with a pear shaped cross section), working your way around the pit. Twist it in half, and place the pit half on the cutting board (not in your hand, or you might find the next step involves thumb removal). Take the knife and swing it into the pit, then twist the pit out of that half. Now cut the halves into quarters, and just grab the top of the peel and pull it off in one big piece if you're perfect, or in a bunch of crumbly tiny pieces if the avacado sucks. Cut off anything you don't want to eat.
How to tell if a lime is juicy: 
The peel will be smooth and shiny. If the peel is matt and bumpy, it won't be a juicy one.
How to dice an onion:
Peel it, leaving the root intact, and cut it in half across the root. Place half of the onion flat side down with the root facing away from you (we'll call this north), and make north-south cuts across the whole onion that don't quite go to the root (so that it doesn't come apart just yet). Now turn the root to the west, and make north-south slices from east to west, stopping when you get close to the root, which you can now toss with the peel. What you have on the cutting board should be perfectly diced onion.
How to choose and dice a jalepeno:
Pick a red one if you can. They turn red when they have just the right amount of water stress during growth, and red jalepenos are the most flavorful. If you see little brown lines in the skin, those indicate a spicier pepper. Cut off the stem, cut lengthwise strips and then line those strips up and cut them into tiny pieces. Keep the seeds and pith, that is where most of the flavor hides.

Assembly:
Put the diced onion and jalepeno in the bottom of a large bowl. Add the salt, mix around with the spoon you added the salt with. Now add the lime juice, stir again and try to get the lime to cover all of the onion. Let it sit for 10 minutes - the lime 'cooks' the onion a bit, so it is important to let it sit in the lime juice a while before you add the avacado. Place the peeled and pitted avacado on top of the onion mixture, and get out a potato masher, or a fork if you don't have a potato masher. Mash it up thoroughly. Also stir a bit. Then mash some more. No big chunks of anything should be in there, if you did everything carefully.