The first thing you have to ensure is that you have everything, and I mean EVERYTHING in the proper format for it to be accepted by the submissions department. Feel free to shoot me a PM and I can steer you in the right direction of some non-online resources regarding this.
Once this is accomplished you have a large choice between two ways to go IMO. Getting an agent, or not. This depends largely on your financial position.
The most important bit of advice I've heard is : Do not be discouraged by rejection. In fact, expect it, and try to learn from it. J.K. Rowling was rejected nearly a dozen times after she got her script in the proper format etc before she found a publisher for Potter, and she's richer than the Queen now. Also, you CAN bipass the production people/companies and go straight to a director with your idea. Spielberg for example will take ideas/submissions, but get this, they have to be 25 words or less for him to be sold on even looking at what you've got.
I know a little about TV, more accurately I have a friend who knows everything, and I assume that's the direction you would think your script would be going.
I have a good high school friend who has directed and produced two household name TV shows(one is on Comedy Central) in addition to loads of other stuff, as well as know the Director/Producers from Blood Diamond, as they were the same guys who did a documentary movie called "Shadow Company", based largely on the Private Military Company I worked for during their production. I also worked as an extra on Legends of the Fall for him previous to this with a bunch of x-Army hooligans (15 seconds of my 15 minutes of fame are in the WW1 charge scene with Aidan Quinn, haha). Anyhow, when you get the stage where everything is in one sock, if you think it'll help, I can ask the former who is more into the TV scene what road is best taken for you, and if he has any ideas regarding contacts etc.