DECIDE BETWEEN PRE-OWNED AND PRE-CONSTRUCTION
If you purchase a pre-owned (resale) condominium, you'll see exactly what you're buying. You can shop around, walk through various suites and pick the one that best suits you. Even if it needs some work, you can be secure in the knowledge that you got pretty much what you expected.
If, however, you decide to purchase a pre-construction condominium, you're entering the realm of the unknown. Sure, you can view sketches in the sales office but have no idea what your unit will look like once built. Still, there's an attractive trade-off: you'll be the first owner of the unit, and everything in it will be brand new.
If you find it hard to visualize what your new space will look like, view similarly sized units in other buildings. It'll give you a feel for they type of space you are talking about when trying to choose a unit from a plan.