Apart from the fact that most circuits in the UK have a climbing crosswind leg, from 500 to 1000ft. The change from climb to level flight is done using the APT method...
A... Attitude.. Whilst climbing at climb speed, and 50ft before the required height, push on the control column to reach the circuit height (1000ft.)
P... Reduce power when you reach the cruise speed.
T... Trim off the force you are pushing on the column. (generally push about two knobbles on a Cessna trim wheel.)
To make the descent part of the circuit, it is just the reverse of what you have just done, but in the PAT order...
P... Power down for descent, usually 1700rpm for Cessnas.
A... Attitude.. Pull back to reduce your speed to the approach speed 70 knts.
T.. Trim off the control column forces (pull back those two knobbles)
If you trim out correctly you can loosen your grip of the column, and the aircraft will maintain the correct glide slope and speed all the way to the runway. Just add or reduce power as needed to reach the exact spot you want on the runway.
To make your circuit more hectic, you also need to do the pre-landing checklist, Radio calls to the tower, adjust the Carb-Heat, adjust the flaps, and keep a good look-out for other traffic.