The basic steps of practicing meditation, understanding yourself and your own energies, etc. are quite important for the strength of your own magic. I've said it before, but being comfortable and confident in your own skin means a great deal.Being familiar with whatever ritual tool you use, and using symbolic methods (casting a circle, utilizing runes you are familiar with, using an athame or wand to direct energy, etc.) can also help you reach the proper mental state and gather and control more energy.
Various incenses and herbs are supposed to be great as well. Dragon's blood, for example, is a resin created from a plant root. It is said to be quite good for empowering magic.
Any other such method you read about can usually be used to empower yourself and your magic.