I will admit that I have not dealt specifically with situations such as yours - however in my experience relationships can be cultivated in similar ways no matter what the situation. So..... I would approach talent agents with an attitude of "giving" if you will. That is to say it's best to approach them by giving them something that they value and making them aware of ways you can help them and how a relationship can be mutually beneficial.
One BIG word of caution.... do this with integrity!!!! People can easily see through phony people and don't like to be manipulated.
Be assertive in your introduction but don't be too eager to get a "job" right away. Present yourself as confident!