Best Tips for how to "network" for those seeking employment.

I personally feel taking a class at a university helps with job seeking. You sometimes end up sitting next to someone already in the field you are seeking. Also, there are social groups for each concentration so your not shooting in the dark when networking.

There are a ton of threads on here about this topic.  Hit up the search bar and you'll find a few.  

Everybody knows that "it's not what you know, it's who you know" that matters these days. SO... for those seeking employment, how does one go about developing a personal and professional network, and then how do you turn that network in to some legitimate job opportunities?