As Derek noted, there are contests. A win can get you an intro to agents and/or managers.
It's also worth cold calling managers in particular. The success rate wil be abysmally low, but even if you can get one out of a hundred to read your pilot, it's time well spent. This can also work with production companies, assuming they do TV, and they are generally interested in stories like yours.
If you have a feature agent, it would be best to go through him/her.
Pilot scripts are more likely to be used as work samples for staff writing jobs these days. TV agents are generally more interested in placing new writers on staff, so they can earn steady commissions and build careers. It's possible for new writers to sell pilots, but it's uncommon.
The standard approach to getting a TV agent is some combination of networking, working lower level industry jobs, getting recommendations from connected people, and doing whatever you can to stand out from the crowd. Recently I've heard people recommending attendance at out of California festivals and conferences as a way of getting closer to power players when they don't have their defense screens all the way up. Haven't tried this myself.
One woman I worked with followed these steps: office PA > set PA > writers' assisstant on that same show > one script as a freelancer on that show > other staff jobs and writing assignments. Another man I worked with followed a similar track: writer's asst for one showrunner, then staff writer on another show.