well, when i stained, i first sanded everything down with some 80 grit to get rid of the poly coating on top. after you have sanded thoroughly, move up to some 120 grit and sand again, making your wood smooth. this part is crucial because the clear coat will prevent any stain from getting through and will make your project look horrible. now once you have your grips down to the wood, you can go ahead and apply a coat of pre-stain. this will allow your grips to be stained more evenly. next you use any stain you like (make sure its darker). i used two coats of stain. when you let that sit overnight, you should be ready to use your clear coat. sand again lightly with your 120, and then put on a thin coat of poly. read the directions as to make sure how long you have to let that sit. after it is dry sand again very lightly with your 120 to get rid of all the bubbles. and repeat to however many coats you want.
good luck, Nick