Experience these different levels of meditation: lying, sitting, moving and standing. Which one are you drawn to? Each will help the body relax so energy can flow. Some postures will help you increase energy.
If you are restless or have physical difficulties, start by lying down and placing your hands over your heart. Close your eyes and relax. Notice your breathing. Allow your breath to be natural.
When you're ready, try a seated meditation. Close your eyes and focus on one thought or object until your mind drops away naturally.
A moving meditation is considered the highest level of Taiji. In this state your body moves yet your mind remains peaceful helping you to acquire energy.
The standing meditation is a form that allows your body to act as an antenna to receive energy. There are various kinds of standing meditation. Here's one I use in my Dragon's Way Qigong program: The Dragon Stands Between Heaven and Earth.