There are some basic elements to "higher performance":
-Rail foil, generally speaking (and we're talking really generally here, but since you are trying to get more performance than a funshape this should hold pretty true) the more "foil" the rail has the more HP it is. More foil = less volume = cutting into the wave more and better planing once you get up to speed. I bet your current board has really boxy rails, find something less boxy... sharper parabola for lack of a better description off the top of my head.
-Bottom contours make a huge difference in responsiveness and speed, but they are less forgiving the more aggressive you make them. Chances are your current board has a pretty flat bottom maybe with some vee here and there and some slight concave. Concave is a discussion in and of itself and someone else can pick up that ball and run with it if they want. The short story is that concave can increase performance, so try to find something with more concave than what you have.... just don't go crazy with it.
-Rocker: Again a whole discussion by itself, but suffice to say if you get something with a more HP rocker profile it means the rocker is tuned for high performance maneuvers and not paddleability or ease of catching a wave... preference can vary widely depending on your taste. If you're looking for tighter turns and making more critical sections, look for something that has a little more rocker on both ends or maybe continuous rocker, or maybe more flip at the nose and tail but flatter through the middle, or maybe......
-Length.... Being able to surf "high performance" requires (let me remind everyone we're speaking in extremely general terms here) a board that fits into the pocket, can match the curvature and essentially dominate the waves on which you intend to shred the gnar. Don't get all crazy with riding what Kelly rides, just think about going shorter..... and I'm talking bigger than 5'2".... Probably something low to mid 6's in your case.
-Fins..... do we really need to get into this right now? I'm hungry, dinner's almost ready and I have a hot date with some power tools and black walnut at 8.
If your from NJ contact essence surf and consider making a 5-10 copy of the Hayden shapes hypto krypto. The dimensions are really fun and could really help you progress from fun shape to shortboard. Good luck
If you don't get in the water frequently... and by that I mean surfing even on those marginal days... don't go too far with a performance board. I think you're right by saying, "higher" performance. That said, I'd go with something more like a shortboard in design, but still carrying some foam.. a "big guy" shortboard, some would call it. I've always told people in your situation to look into a hybrid shape, which is an oversized performance shortboard... a funshape with a more performance oriented outline, foil, bottom, rails, etc.... but shorter and narrower, with only slightly less volume. A step up in performance, but not such a big step that you'll struggle for 6 months before you start to get the thing wired. Something you'll be able to jump right into, feel a noticeable difference, but not waste a dozen swells trying to figure it out.