I've never negotiated such a deal so I'm seeking any advise. 

Keep the relationship a professional one from the start.

There are some really nice old houses that once fixed up, both students and professionals love to rent because of their close proximity to the city and campuses. 

I was recently at a meeting where the speaker stated that many investors made their seed money in other ventures such as owning restaurants, a professional career such as CPA, etc.

You can google "We Buy Houses in LI," call bandit signs if you see them, go on Craigslist and seek out ads who are looking for properties, or even post an ad stating you'd like to work with investors to bring them deals and locate investors that way. 

Build relationships with multi-family property owners and real estate professionals in your area.  

not very professional especially for a Realtor.  

What would you consider the a/b areas where you will get professional type renters?

Looking for fellow investors seeking to network in Southern California and connect with deals

A lot of times the less professional they look, the better they work.