It is imperative that you have a basic understanding of how to use weights before you commence a weight lifting program.
With this in mind, here are some basic but important weight lifting tips to help you on your way.
First and foremost, never try to lift weights that are beyond your current level. Many amateurs make the mistake of thinking if they switch to the heaviest possible weights, they will suddenly become big. This is not the way it works at all and you will injure yourself.
Ensure that you are warmed up properly before you start your routine. If your muscles are unprepared for a movement you may damage them, which will lead to time out of the gym and a drop in your level.
Try to breath freely and evenly as you complete movements. Holding your breath is not advisable, even though you might find yourself doing it without realising.
Aim to be still as you complete reps, as well as clean and even with your movements. Do not be loose, or else you will, again, risk injury.
If you are uncertain about a movement or are pushing for a new weight, get a spotter to help you out. Spotters are not just for safety, they can actually help you progress by getting you through the last couple of reps.