[baytrailcat]

Youtube is a great resource to find a general consensus of the common wisdom.

You can also record yourself with a tripod and camera and watch later.

Another way to learn is to watch other people (People who look like they know what they are doing) in the gym. If you are the outgoing type, you can spark a conversation with them and ask them to watch your form (or spot your lifts). You get lot of practical knowledge this way.

Form is everything. If you cannot do the reps with proper form (and breathing), reduce the load till you can, then slowly progress. It is worth it.