Do you have any ideas as to what you want to haul and what type of driving you want to do? That determines everything. The 3 G's are most lucrative- gas, groceries, and garbage. If you do short haul, you will be home every night, but won't make as much. If you do long haul, you have the potential to make the big bucks, but you will be gone more than not, and you will probably lose a wife/ girlfriend along the way. If you get in specialized trucking you will generally make more money, or something that requires some sort of formal barrier. If you get the Hazmat endorsement, you will make more money, especially hauling bulk fuel, but thanks to the Patriot Act it is a real pain to get and keep active. You will probably want to look into getting the TWIC card as well so you can go into ports.
Keep in mind most truck schools are "factories" and turn out as many drivers as they can and the quality isn't always there. If you are under 25, it will be hard to get a job. If you have a bad driving record, it will be hard to get a job. If you have never driven, it will be hard to get a job. If you are under 21, you'll be stuck trucking within Louisiana's boundaries, and even then, you cannot haul goods that came from out of state or are destined for out of state as that is interstate and you need to be 21. Get the experience any way you can, but realize your first job might not be your dream job.
I would recommend getting every endorsement you can. I assume you are getting class A, but be sure to take the tanker and double/triple tests too. You only have to take a written test and they are fairly easy, and you never know when you will need them. It has come in handy for me when I least expected it.
There are some MAJOR changes being implemented with the commercial license. The regulators are going overboard, and with the FMCSA's implementation of the CSA program things are getting stricter and stricter every year. If there are safety violations it will be attached to your license. It is trying to make drivers more responsible for their vehicles. The regulators are also making CDLs have a 5 year expiration limit. States used to set their own rules, and some had higher limits (such as 8 years), but in the future it is going to be 5 years no matter what state you are in. In the past medical cards were only required when you had your ass in the truck. Now you need a VALID medical card at all times, otherwise your CDL will be suspended. No active medical card = no CDL. This is a new requirement that will be fully integrated by the states by 2014. Some states are already adopting it. In the future you won't need to carry a medical card with you when you drive as it will be tied to your license. Be prepared to deal with this mess every two years and when you renew your license. And government agencies aren't covered by HIPPA, so whatever person is assisting you at the DMV will have access to your entire medical history, such as the temperature and sugar count of your urine. Are you fully comfortable with that? I'm not, but that's the world we live in. Just looking at some random states you will see how far sweeping these changes are-
I would say give it a try, and maybe the regulations are a good thing because it will prevent some real clowns from bringing everyone else down. And my only other piece of advice for you is never do any drugs. If you get in a wreck (even if someone hits you and it is 100% their fault), every commercial accident requires a drug test, and you go from being 100% innocent/ not at fault to possible partially at fault. Always be clean. And if you do get busted it goes on your license and you will have a very difficult time getting another driving job again and will have to pay for a mandated drug treatment class. I've seen some good drivers fall into this trap, and it is sad that after 15 or 20 years solid years of trucking they are suddenly out of work and unable to get another driving job because they are a liability. And remember when driving commercially, you can be inspected at any time you are on the road by the police for no reason whatsoever. Most of the time they will be doing brake inspections and trying to look at your log book.
Good luck and keep on trucking!