Third, pick a company that actually has a reputation. In other words, do not be ashamed to consult with your friends. You need to get a company that has worked for a lot of people, not some travel agency that seemed to pop out of nowhere. A travel agency that has a reputation will also have a reputation to uphold, so they cannot simply take money from you and make your last minute travel horrendous.
Fourth, always scout around for a lot of travel agents. There will surely be many travel agencies in your area: some big travel agencies may have a lot of clients and they might not be able to give you the attention that you need for last minute travel, but they could also be used to catering to people who are on last minute travel quandaries. Smaller agencies can give you the personalized service that you need, but they might not be used to handling last minute travel arrangements. Look for many travel agents and then have an agency that exclusively handles your last minute travel needs.
These are only a few tips that you can use to help you get the travel deals that you want. Last minute travel can be a big hassle, but if you know what agencies will work well for you, you won't have too big a problem.