A friend of mine got me hooked on making fresh, homemade mayonnaise a while back. There is a special technique that you need to use in order to be successful.
Until I began using this special technique I have always failed at making homemade mayonnaise. If you want your homemade mayonnaise to thicken properly you need to use a special tool. The trick is to add your oil at a drizzle. I use a candy making bottle that adds just the right amount of oil in a very slow flow. Works like a charm with my hand mixer.
If you'd like to learn more about this you can visit healthy-family.org and read more details about how I make homemade mayo from my recipes page.