Know your airplane. Know your approaches. Be confident. And like Skip said, BE AHEAD OF THE AIRPLANE! On my Instrument ride we were in VMC on final doing an ILS when the A/C's glide slope actually went dead. What did I do? Straight to the LOC approach #s. Definitely easier to do because I was using a kneeboard. Have scratch paper out so you can draw a holding pattern if you have to. Just be sure to pay attention and don't get lazy. If your instructor has done a good job then just do what you have done on every training flight.

Checkrides are 90% in your head. Before you know it you'll be working on that next rating. You'll do great.