meditate
let it come naturally
who cares where the tan-tein is
There are 7 major Tan-tiens in ur body. For Ki reference u only need to concentrate on ur 2nd tan-tien which is located 2-3 inhes below ur navel. For full reference u can read the energy levels article at veritasonline.net
Going for meditation to improve visualisations is the best technique but it is slow. For fast effect just clear ur mind of everything. Don't let any thought come into u[|)]. Now imagine whatever u want to do. Focus and don't loose concentration.[8D]
Everyone can and does visualise. When you recall things, when you remember what things looked like, that is visualisation. When you imagine what things could look like, that is visualisation. If you're having problems then try meditation.
I just don't know how it's done, and where is the Tan-Tein located?