Let start first with why should you choose a travel agent. When it is a question about organizing a trip for one or two people to a place which isn't too distant, you can handle it by yourself without giving money to an agent or agency. Now it's so easy just to buy tickets and to go. But if you plan going to a totally unfamiliar country or a country whose way of dealing with administration is very different from this you are used to, then maybe using an agent can be extremely helpful. Also when you have to plan the trip for more people it might become a little bit too stressful so if you let someone do the job instead it can be more pleasant experience for you. What's more, you can count that if you have chosen a good agent you might receive help if something fails like for example the booking of your room. Then the agent could act like he/she is some kind of your lawyer so you won't end up with nowhere to sleep. Travel agencies can help you with the needed information and it will be much more than this on the Internet.

You can always start with asking around by the best travel agency and if there are some relatives, neighbours or friends who can advise you which company to choose you can follow their recommendations. You can even search the companies in the phone book, the way is not that important. But before that make sure you have checked whether the specification of the agency and their past experience cover the trip type you are interested in. For example, if you want to organize a vacation for the entire family somewhere on the south you can't hire a travel agency specialized in business trips, right?

Other question is whether you should settle in something small or look for a big agency. It's common way of thinking that the larger companies can offer more when it comes to suppliers with services and added value. They actually may offer you wide range of choices and more covered areas, but there is something else. It is a common practice the best agents to leave their big employer and to start their own business in a small agency. It can give them also better relations with the clients and with the rest of the staff so it's the usual thing to do. So in case you need not so complicated services and you prefer personalised attitude in the agency, you might find the smaller agency even more efficient.

If you want to be confident in the professionalism of the chosen agency you better choose one who is licensed and you could also ask to see if there are some qualification certificates in the agent's office. However, when you choose a licensed agency you aren't guaranteed to escape frauds, it's more like insurance.

Emergency service in hours not in their usual work time can be important issue in the decision you will take. You might need some extra help during the travel toward your destination and if something happened outside the normal working day you can't count on your agent, so you might consider this requirement as important too. Of course, not all of the agencies provide their support for the clients at any time. But you can feel satisfied with less like for example some of the companies can offer emergency center they work with and which is going to help you if your call is not in the normal working hours. It doesn't guarantee the best service, because sometimes there are problem in coordinating between the two teams, but in the most cases it is not so bad option. 

Finally, don't expect the best agent won't charge you higher than the others, after all his/her services worth more and he/she knows it. So based your decision on the added value and the price and sometimes it might take some compromises.