There are a few different types of bustle. Some have hooks sewn into the dress, some have ribbons that you have to tie together under the skirt. Whatever the style of your bustle my advice is practice!
If you can, take one of your bridesmaids along to your final alteration and have them explain the bustle to your bridesmaid. And then practice, practice, practice. The chances are you will be doing this just before the formal introductions of the bride and groom and most likely there will be little to no time in the scheduled timeline for bustling. If you know how it should look before and where the hooks/ribbons are then this will be a stress free part of the evening.
If your bustle is complicated and has a whole lot of ribbons that need to be tied together, have your seamstress label them, either with numbers or color dots so you know which ones to connect them too. I have seen bustles from one simple hook to 25 ribbons that took 25 minutes to figure out. If you tie the wrong ribbons together you can end up with a lop sided dress and you still have that first dance picture to take.
The hardest dress bustle I have ever seen require the bride to take her dress off, as the bustles were high up inside and the bridesmaids could not get near them, however I have heard stories of brides "planking" in order to get the dress bustled... :)