There are really only two things to concern yourself with in choosing your surfboard.
Float and Glide
While these are the only two functions your board needs to perform, the variations taken by designers to achieve these things can be pretty wide-ranging. So how do you decide which one you want?
First, you must consider how you want to ride a wave. Would you prefer catching smaller waves with ease and being able to cruise in a more relaxed manner? Then, you ought to lean towards a longer board (meaning 8' and up).
Perhaps you want to slice, pump, and feel like you're on a skateboard. Then, you're leaning more towards a shortboard (roughly 6' and shorter).
The difference between these two, short and longboards, is that shortboards have less volume, so they are more maneuverable while longboards have that extra volume, so they are much easier to paddle and catch waves, but more difficult to turn.
So would you rather surf with more speed and energy, or with less effort and a more relaxed styled? There is no right answer, and in fact, odds are you will want both if you are looking to surf consistently.
This is surfing at its bare minimum. As you can guess, there are folks who like to surf longer boards more aggressively just like there are those that prefer shorter boards to surf more casually. It is all personal preference, and the more practice you get the better you'll be able to determine what it is you want in your surfboard(s).
A nice general rule-of-thumb to consider is that the smaller the wave, the bigger the board you'll want.
Volume is king when it comes to easier paddling and getting into waves with less effort, so make sure to go for a board with more volume towards the beginning. Once you're comfortable here, start to look towards shorter boards with less volume in order to start practicing your turning, pumping, and agile maneuvers.
Have fun!
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