Finally I decided to answer this tough one:
The knees are flexed/bent, hips are lowered, on toes, upper hody erect/stable, the racket is held in front and nose high (volley grip).
Your net/court positioning depends on where your partner is going to serve:
If your partner is going to serve out wide in deuce court, you may stand half-way between service line and the net and cheat more towards single sideline.
If your partner is going to serve up the T, you may stand half-way between service line and the net and cheat more towards center service line.
If your partner is going to serve in the body of the receiver, you may stand half-way between service line and the net and position yourself in the center of the box.
Through trial and errors which are many in tennis, you will be able to modify your stance. The above is a general guideline.
Mirror the above positioning for the ad court also.