There are always a plethora of grips floating around the studio. Though I am not a huge fan of grip aids, I understand their purpose and use them on occasion when doing risky moves myself.
I do not recommend them for someone new to pole fitness. As with any new sport or fitness regimen, you need to let your body adjust to the elements. Sweaty, slippery hands are normal when attempting your first spins. You will eventually understand how tight you need to grip the pole and your skin and glands will adjust to your fabulous new hobby.
Once you start advancing and learning to invert, you will need to have a proper grip. If this doesn't happen naturally after practice, seek a grip aid. Bad Kitty Exotic Wear (www.badkittyexoticwear.com) reviewed a handful of grip aids and provided this fantastic chart.
See Bad Kitty's complete write-up of the products here.
One of our favorites at Urban Studio is iTac2. It is perfect for executing tricky, new pole dance moves, but not recommended for spinning or for sweaty hands/poles. Yes, poles can sweat too! The major downfall of iTac2 is that it can be very difficult to get off of the poles.
A way to improve your grip naturally is to thoroughly warm up. Use your pole to warm up too. A warm pole and slightly sticky (but not too sweaty) body will help you grip the pole.