I just got my February 2013 Fine Woodworking magazine and they were talking about fitting tenons. It was a good article, but I do something a little different (not necessarily better) at least for the tenon cheeks. Their fitting involves using a shoulder plane for the shoulder and a skewed rabbet plane for the cheeks.
Chris Schwarz talks about it a bit here (since I can’t share the FW article).
So for what it’s worth, here’s the way I do it.
Marking the tenons.
Cutting the tenons.
Using a rasp to round the edges of the tenon.
This is what I do that’s different. I use the router to trim the tenon and keep the tenon centered. I trim on one side and flip it over and trim at the same depth the other side.
Once the fit is close, I chalk the tenon ..
.. and I look for rub spots.
And I generally get a snug fitting tenon.
PS. I also like this blow by blow: A Primer for Mortice-and-Tenon Joints