When buying your first Surfboard the main rule to remember is the bigger the better (within reason) you may not want a 13ft monster that weighs a ton! But you also don't want a high tec carbon fibre short-board that's as buoyant as a tooth pick!
For the best results and the quickest way to improve your skills, you need a board at least 1 foot longer than you are tall, though I would recommend to go as big as you can, but which you can still carry easily to and from the water.
A Longboard shape is the type you are looking for, Longboards have a very wide round nose compared to a shortboard which has a point.
The ideal board will be between 2.5 to 3 inches and around 20 to 24 inches wide.
Fin type is not massively critical though I'd recommend a 3 fin set-up as the fins are smaller meaning you are less likely to damage them riding into the shore.
Too small a board and you will find catching waves very difficult and then when you do catch the wave it will very easily stall once you get to your feet.
A bigger board wont need a powerful wave to get you moving, it will provide a stable platform for you to stand on and will have a better planing ability meaning it will keep momentum up giving you nice long fun rides from the outset.
A board as I've described above will give you the most fun and you will advance your skills very quickly, then you can start looking at a smaller board.
There is a fantastic array of boards out there to choose from, the main 3 types are:
Foamies - If you have had a lesson in a surf school this is very likely the type of board you used, they are cheap reliable and soft should you land hard on them!
They are a good first board cheap and robust, though you may find yourself wanting to upgrade to a "hard" board.
Moulded - Theses are fantastic boards available from a number of manufacturers, the main manufacturers are BIC and NSP.
These boards are produced from a mould and available in a number of composite materials from Epoxy or Polypropylene.
These board are very buoyant, very robust yet still very light and manoeuvrable, they are the ideal beginners boards.
There is a massive selection of these boards available 2nd hand on Ebay, however they are reasonably priced new. Keep an eye out for damage, though it's fairly cheap to have holes repaired usually costing around £20 for an average repair.
Custom - Custom boards are the ultimate in performance and weight, The traditional way to make these boards is to hand shape them meaning no 2 are the same. However as technology moves on a number of manufacturers have appeared that use "shaping machines" meaning boards are made to a CAD template rather than shaped by hand in the traditional way.
They are very light but also very easy to damage and need care to look after them, generally people will progress to a Custom board after a few years on a moulded board.
Custom boards are more expensive then the other types as they are crafted by hand rather than mass manufactured.
So there you go a basic run-down on the best board to buy when you are first starting out - See you in the lineup, Ben Wavetools Surf Shop