How can I make my homemade potato wedges crispy? How do I make my wedges go nice and crispy in the oven?

I usually season them with a cajun mix, add a tiny bit of oil, and cook them in the oven on fan-bake at about 200 degrees (celcius). They come out okay, but not amazing.

What can I do to make them come out a lot crispier, while still using a normal household oven? Would more oil improve their texture, or do I need to crumb them maybe?
You could put them in a pan of boiling water for 3 or 4 minutes (not so to they're cooked through) before putting them in the oven. The potato on the outside of the wedges will soften and cook a little bit which will help the outsides crisp up a little. Make sure you allow them to drain completely before you put them in the oven.