to trim out the fender you will use some tape to map out the path you will cut, take a grinder with a cutoff wheel, start at the bottom of the fender trimming about an inch off at a time, turn the wheel till the back of the tire comes in contact to the fender, mark and trim, the tape is also put on so your paint doesnt chip off, to get a radius on the top of the fender take the tape and a pencil and trace around the tape or something with a round edge.
I have personally taken a 35x12.5x15 in Pro comp M/T and fit it in with a 4 inch lift on my 98 XJ with a large amount of trimming in the front as well as the back. If you have any questions PM me, OH ya the seam that runs down the back of your wheel well cut those in 6 inch increments, and beat em down with a BFH( You may have to take the tire off to get good whacks in