Aren't tapers great? You get to swim less yardage with less intensity. At the same time, you get more stressed out emotionally, worrying about how you feel and what you could have done better. But, the best benefit is walking up steps without being exhausted!
When I taper, I take it very seriously. The main theme I follow is one I've heard before: "I'd rather be a week too rested than one day short of being tapered." Too often we feel great a week or two after the big meet. The best 1500 meter swim of my life (a distance event no less) was after a seven- week taper.
What am I trying to accomplish and avoid during a taper? I try to get rested while maintaining a good feel for the water. I firmly embed in my mind my goals and strategies for the swim so that the morning of the race I know what I am going to do. I want to gain confidence in my pace. And, I want to relax.
While I do pace 100s for distance events, I try to avoid over-sprinting during the taper for a number of reasons. It is my view (and there are many of opposing opinions) that by the time you taper, you should already be in shape, should have done ample speed work, and can do more harm than good by testing yourself and sprinting a lot immediately before a meet. It is very difficult to get out of shape in a few weeks if you start with a good base and are doing a lot of maintenance work.
Doc Councilman often gave us a framework for a workout during taper and let us adjust according to how we felt. Four to five weeks out, he would cut the yardage and increase the speed work. Then with three weeks to go, we would usually step down the yardage and speed work considerably, doing a lot of low-end aerobic swims.
We would talk about diet, sleep, the races etc. I think this helped us focus on the big weekend for those three weeks so that, when we got there, the anticipation had built, and we walked into the pool with a well-defined purpose. (We have all been to meets where our minds were not in the pool, this helped us avoid that.)
One of the potential hazards of tapering is the mental aspect. Usually, as response to a changed stress, there can be a period during the taper when you feel lousy in the water and you will question whether you are in shape.
This is when the coach can be crucial -- to convince you (and himself) that this is normal and not to worry. While it is normal to feel this way, it is crucial to keep faith and to believe that this feeling indicates that you are doing things correctly.
It is also helpful during your taper to place the race days. If your pre-race meal consists of Milk Duds, chips with salsa, and Budweiser, then practice having that meal before you swim during your taper to make sure it sits well with you.
Planning your warm-up is also beneficial. Doc used to have us decide three weeks out how we would warm up for the meet. His rationale was that he didn't want us not to do enough or to do something that our bodies weren't used to on the day of the meet.
All in all, taper can be a highly individual thing. My own goals are to rest, to feel comfortable with what I'm doing, to plan my races, and to internalize (visualize) the race for a few weeks so my body knows what to expect and to trust that I am in shape and it is now time to rest.