1-Use russet or baking potatoes, their high starch content will help hold the latkes together when frying.
2- You may grate potatoes and onion by hand, in the food processor or blender.
In the food processor, grate first, then change to the chopping blade and pulse until the mixture is grated but not mushy.
In the blender, you will need to first cube the potatoes and be careful not to make a puree.
3-After you squeeze the potatoes, you will see a whiteish sediment in the bottom of the bowl; save two to three tablespoons of this starchy water and add it back to the potato mixture.
4-Olive oil does not work well for frying. Instead use canola or peanut oil.
5-In any recipe for potato pancakes is very important to use enough oil, keep 1/4 inch in the bottom of the pan at all times.
6-The oil must stay at a hot enough temperature for browning, so after adding more oil you'll need to wait until your pan resumes the proper temperature. It should take 3 to 5 minutes for the latkes to brown on each side. If it takes longer they will be soggy. If they brown too quickly, the insides will not have that creamy texture we all love. Stay with the pan constantly to avoid burning or undercooking.
7-Do not crowd the latkes in the pan. I usually have two pans going, especially when I double my recipe for potato pancakes. It's more to clean up, but cuts the cooking time in half, so it's worth it.