direction of where you want the ball to go, and low.

The main purpose of the volley is to keep your opponent constantly on the
run, moving him about, and preferably up and back, by cutting off the
flight of the ball. Most players can run all day sideways, but will
eventually tire if you make them run up and back. Like body punches in
boxing, forcing your opponent up to the front wall with deftly placed
volleys will eventually take its toll.

Miscellaneous: Generally all Squash Tennis strokes should be hit as low
as possible--within a few inches of the front "telltale." This will take
time and practice, but pays high dividends. A low ball invites the
aforementioned nicks and keeps your opponent hurrying and scurrying. The
chances are better that, when hit with the proper amount of pace, a low
ball will die before it gets to the back wall.

When a ball is hugging the side wall, don't attempt to "pick" it off. It
is far easier, and your percentage of success is far greater, to "scrape"
the ball off with a very loose wrist. Your other alternative is to hit
the ball right into the wall and hope it will angle off and travel to the
front wall (see fig. 4 [To retrieve wall hugger, hit ball right into
wall.]).

Service: The proper position prior to serving is with the feet as close
to the "T" as possible. This location will help you to put your service
in the desired place, which is parallel to the side wall. In other
words, you reduce the angle. In addition, the "center" of the court is
the ideal position from which to cover your opponent's return (see fig. 5
[Forehand and backhand service positions.]).