The speed at which the clock runs is determined by the length from the top of the pendulum to the pendulum bob. Below or in the middle of the pendulum bob is a small nut which can be turned either way, moving the bob up or down.
To make the clock go slower, the pendulum must be lengthened so the bob will need to move downwards (usually turn the nut to the left) and to make it go faster, it will need to be shortened and the bob will have to be moved upwards (usually turn the nut to the right).
It is worth noting that different clock movements produce varying degrees of accuracy depending on the type regulation mechanism and whether it has additional mechanisms to assist accurate time keeping. It is also not unusual for some spring driven clocks to run slightly slower as the clock spring runs down throughout the week.

Setting to time

To move the hands some clocks have a nut to turn the hands on the back of the movement inside the clock. Mostly you will simply turn the hands to the desired time.
On a timepiece (that is one that does not strike or chime) you should be able to simply move the hands to the correct time.
There are different sorts of chiming / striking clocks. On a rack strike clock gently move the hands around to the correct time as with a timepiece. If you pass 12 o'clock on the way you must stop and let it strike the full 12 notes before continuing to the correct time.
On a plate strike you must let the clock strike all notes on every hour and half hour.
If when you turn the hands and the clock strikes a different amount of notes to the correct hour then it is most likely a plate strike (see setting strike in sequence with the time).

The clock is striking one note at the hour and the numbers at the half past

Move the minute hand to the number 6 to set it striking the numbers. While it is still striking carry on moving the minute hand to just past the number 12. Then set to time.

Setting the strike in sequence with the time

If the clock strikes a different amount of notes to the time that the hands show there are 2 ways to remedy this.
Firstly apply gentle pressure to the hour (shorter) hand. If this moves independently to the minute hand move the hour hand to the hour that the clock has just struck. Then set to time as normal using the minute (longer) hand.
If the hour hand does not move independently you must use the next method. Move the minute hand to the 12 to set it striking, then as the clock is striking keep moving the minute hand round past the number 12 until the hour hand reaches the hour that the clock has just struck.

Setting your clock on beat (getting an even tick)

The beat or tick of a clock must sound even. That is the time between each tick tock must be even. Different styles of clocks have different methods of setting the clock on beat. In every case though the object is to move the crutch (the bit the pendulum passes through and swings from left to right) to the left or right to even out the tick.

Winding your clock

Spring driven clocks - (for example mantle clocks, French clocks and German wall clocks)
Wind these clocks until the spring comes to a definite stop. A lot of people worry about over winding a clock however this is extremely unlikely to happen due to the amount of force it would take.

You may have one, two or three key holes for winding, for the chime, strike and time. Generally you must wind all three, only winding one may stop the clock and possibly in rare cases damage the strike. Weight driven clocks - (for example grandfather clocks, long case clocks and Vienna clocks).
Wind these clocks until the weight is just beneath the wooden platform the movement sits on. As with spring driven clock you may have up to three to wind, wind them all. Do not wind until it comes to a stop but leave a little bit at the top.