The reference stiz quoted is good info. Bear in mind that:
a. not all circuits are left hand (more like left-hand unless otherwise stated) FS doesn't care as a rule so "when in doubt, go left." Right hand ( non-standard) circuits are normally set for tower view issues, crossing runways, noise abatement, terrain issues. Left-hand circuits keep the pilot of a side-by-side seating a/c with the best view of the runway.
b. the entry from outside--
*if entering from the downwind side, enter the downwind at a 45 deg. angle (think a highway merge). this allows you to adjust speed to fit with existing traffic
*If entering from the downwind 'side' but from off the departure end, just fly straight into the downwind leg but watch for traffic climbing out and on cross wind.
*If entering from 30 degrees of final it's generally accepted that you may fly 'straight in" but should establish yourself on final well back so you can see other traffic in the circuit AND they can see you and adjust their downwind to follow.
*30-90 deg. from Rwy heading, it's getting common ( and sometimes dangerous) for people to join to the base leg, but that means traffic in the circuit has to watch for a/c on both sides. better to move over and join downwind at the 45.
*if approaching from the opposite side of the airport the common practice is to cross at mid-field and join downwind while watching for traffic turning downwind from crosswind leg as well as current downwind traffic.
At a controlled airport, join where you are instructed as the controller is working to sequence traffic you may never see.
Want to have a personal conversation with a controller? Cut someone off in the circuit! -although it will likely be a very one-sided conversation:redf:
Other bits... the US has to be different.. they fly 'lights' at 800 ft, jets at 1500 ft for separation and a/c performance reasons. Works but makes it harder to spot traffic above/below you.
Why do you fly circuits to begin? To teach orientation and perception for climb, approach and landing, to get use to standard performance and power settings, to teach how to conform with other traffic. -- all while staying close enough to get down if needed AND because that way you get the most landings in a given time (it's the least distance needed to cover all the performance range.)
At a rough estimate, in 28 years in ATC I saw something like 1.2 MILLION circuits.
Rob