How do I get darker in a tanning bed?

I'm goin tanning tonight and I have been tanning since Feburary and I haven't got as dark as everyone else and I haven't got as dark as I want.I know it's not their bulbs because they just replaced them and I'm in the maximum time for my bed. I don't want to buy a tanning lotion but do I have to because one time I saw online olive oil will help you get darker so I put on my daily lotion& olive oil on top and I didn't even tan! Did I put on too much? Do I have to get a tanning lotion in order to get darker? And if I do how do I apply it? Oh and I know all the risks I'm puttin myself in I don't need a lecture or your s!