Of course firms are different and there are a multitude of sectors to work in and varieties such as in house, temporary, permenant, more contract based work but, on a very general mainstream commercial basis...
If you are looking for a nice fluffy job helping nice people get the jobs of their dreams then you may want to reconsider.
Recruitment is a sales based industry. If you are money/targets focussed, can work under a lot of pressure in a fast paced environment being constantly pushed then it could be your thing. You have to make money or you are unlikely to last very long. Also bear in mind the current state of the job market, recruitment in a recession (depending on the sector) is even more of a challenge.
Can you live on an often basic salary with commission structure (so your take home pay - and could be your job) depends on you getting deals?
Many recruitment agents are on the phone a lot, it's usually very much call focussed, getting candidates in, getting clients in, getting vacancies, persuading clients to interview/recruit candidates, persuading candiates to go to interview/take jobs... No placement means no fee (hence the big time sales side of things). Something goes wrong you could lose a client/candidate for good. Being able to work at speed is also key as there is a lot of competition.
Being very tenancious is a must, if you are shy or loathe to push people into doing what you want them to do (without pushing it too far) then you are likely to struggle.
Many businesses can be plagued by agents and you can spend a lot of time trying to get people to talk to you who really don't want to talk to you at all, let alone give you a vacancy or see any of your candidates. Similarly headhunting for roles and similar.
You also have to be very quick thinking and spot on - you miss the opportunity to say what you need to the one time you get someone to speak to you, you may not get another chance.
Liking a challenge is useful!
It can also be a very frustrating job - people who get interviews and won't go (or don't turn up without telling you) or get offered a job they won't take - in a sales environment there is always an element of failure but each one is a lost fee.
You can put a huge amount of work into setting up a job offer (initial registration, interviews, all the inbetween, offer...) only for another candidate to get the job or your candidate to not take the job and bang goes any fee for all the work you did which means you have wasted time which could have been spent on other fee generating work and, if your candidate pulls out it can have an adverse relationship on any further business with the client.
It might seem a bit OTT to say things like that but, honestly, you don't know how unreliable people can be and the problem with agent sales pushing is by having to try and persuade people to do things they don't want to you it can lead to people just not turning up and disappearing. I've seen someone get offered a fantastic job they seemed well up for on a good payrise, say they'll take it and just disappear into thin air (try explaining that to a client!).
Long and sometimes antisocial hours can often be involved. A lot of candidates will already be working, hence the best times to get hold of them (on the phone or meeting) are when they aren't (ie out of normal office hours).
Business development skills are also key to build and maintain a base of clients and candidates to keep getting work in. Networking is a good skill and can also involve out of hours events.
Knowing the industry you are recruiting for can also be valuable - the less you know the less you can understand what clients and candidates are looking for, identify the right fits, inspire confidence etc...
Some people thrive on the environment though.