Choose a practice based on either an appreciation of the whole of the path of the tradition you have an affinity for, or a knowledge of where the practice is intended to lead.
Always analyse and reanalyse your motivations for practicing.
Once you trust your meditation technique and are confident you know your reasons for practicing it, you should try to bring as much of its method with you, off the cushion and into your life. Every experience you have is part of your contemplative practice. Practice is a way of developing a skilful attitude towards experience, and a method for coming into direct confrontation with it.
And, whatever it's worth, here are some pointers on common pitfalls on the path: