I make hummus weekly, and learned pretty early on that the one thing that makes it taste bogging is lack of salt. Don't be scared to add it - half a teaspoon per tin of chickpeas. It shouldn't taste salty, but any less it tastes like sludge.
Ignore the recipes that include the slime from the tin - either boil your dried chickpeas, or use a tin and rinse thoroughly.
Recipe = per 1 tin of chickpeas add 2 cloves garlic, 3 tbsp tahini, 4 tbsp lemon (approx 1 lemon, fresh is better but bottled is easier) 0.5 tsp salt, cold water as needed for correct thickness.
As for adding olive oil, this is a matter of some debate in hummus-eating countries (think campag/shimano) but there is no need for any. Add a little really good extra virgin if you like the flavour. Supermarket hummus has lots of oil - this is solely to give it longer shelf life. Water-based hummus will last a week, and freezes well.