Any specific type of glass I need to get?
Just tell the glass shop you are building an aquarium. The glass should be normal glass that breaks into big pieces, not safety glass that shatters into lots of little pieces.
The glass needs to be a certain thickness and this depends on how big the tank is.
If the tank is 2ft long x 12 inches wide x 12 inches high, you can use 4 or 5mm thick glass, (5mm is safer and less likely to bulge out or crack).
If the tank is 18 inches wide x 18 inches high, use 6mm thick glass.
If the tank is 2ft wide or 2ft high, use 10mm thick glass.
If the tank is 30inches high or wide, you use 12-15mm thick glass.
If you visit the local pet shop, you can look at their tanks and measure the thickness of the glass. That should give you an idea of how thick it needs to be for the tank.
Buying glass from a glass shop and building your own tank can actually cost more than buying a new tank from a pet shop so work out prices before you try this. Most places that build aquariums to supply the shops, get the glass cheaper than what you or I would pay if we walk into a glass company and buy the glass.