1. I couldnt agree more with the first point, ONLY BENCH ONCE PER WEEK.
However...the second two are a little off.
2. Foot placement is not that critical. For many it is important, but i could care less. I have never planted my feet so that i can keep my back and ass on the bench. Too many people tend to drive with their legs and instantly their ass comes up off the bench. You are working your chest, not your legs!
3. Bench were you are comfortable. Peoples' shoulders tract differently, so do what is comfortable to you. Their is nothing wrong with heeding this advice, but do what feels natural.
Lastly, one of the best ways to improves one bench is through the use of sets of 10 reps. Warmup and then do 3 sets of 10 at a weight at which you can normally do a set of 10. By time you get to the second and third sets of 10, you wont be able to complete them. Try this, i went from doing 1 set of 10 @ 315, after 3 months, i could do 3 sets of 10 @ 315. Currently i can do 3 sets of 15 @ 315.
Example: 135 (15-20 reps)
225 (10 reps)
275 (6 reps)
315 (10reps) for 3 sets
rest pauses (heavier) for a set of 3.
Try it guys, you will be presently suprised. However, you will have to regress at the start, but after several months your bench should explode.