HIM tapering help...

I would recommend tapering for 2 weeks prior to a half ironamn.  (assuming it is a priority race for you)  The first week of the taper (2 weeks out)  cut your volume by about 25%.  Maintain your speedwork.  the week of your race, cut your volume an additional 25%   The week of, cut back on your speedwork also.  Do a few short pick ups (or brief accelerations to race pace)

I usually take the day off two days out.  (typically for travel)  The day before, I do a short bike and a short run.  (maybe 20 minutes and 10 minutes respectively)  Throw in a few pick ups to keep your legs fresh.  if you are uncomfortable with the water, feel free to do a short swim.

Hope that helps.

I like the general plan posted above - but aren't you following a prescribed training plan. One that has a taper built into it. If not, take a look at some cookie-cutter HIM plans out there (on this site too) to see what they do for the 2-3 weeks leading up to the race.

Keep in mind you won't be making any physiological adaptations during your last two weeks of training that will benefit you on race day. In other words, if you try to squeeze in one last hard/long workout thinking it will help - it will just impede your recovery and ability to be as fresh as possible for the race.  So each workout during the taper should be about staying fresh but not losing fitness.  Most do this by reducing volume but keeping intensity.

I don't recommend general tapering periods because it is silly to assume all athletes adapt similar to training load or recover at the same rate from it. While an athlete might benefit from a 2 week taper another might suffer and lose fitness hence a shorter taper will help. In fact for many my athletes a shorter taper is been working better but exactly how many days varies from one to another. They can be as long as 10 days and as short as 5 days.

What *I* would suggest you to do would be to review your logs and see how long in general it took you to recover from your peak week. Also review how long it takes you to recover from very hard (intense) and/or long days.

Also if your HIM is 4 weeks away you should be doing race rehearsals over the next two weeks. In these weeks you’ll train your usual avg per week (i.e. 10 hrs) but one session will be your race simulation which is a long/intense effort some/all at race pace and in which you’ll be able to practice your nutrition. Pay attention as to how long it takes for you to recover from those.  

Using all those should give you a solid idea of how many days it should take you to feel 100% and ready to race. As far as what to do on taper week, nothing special, just reduce your load and do something easy every day to maintain fitness; you can add some intensity to give you a better feel for training and keep legs sharp. Top AGers can get a final fitness boost from this. Some athletes benefit from days off while others don’t (if they do they tend to feel flat on race day) hence don’t take days off unless you know you need them.

Good luck!