The clove hitch is a useful knot for building a climbing anchor. Its biggest advantage over the various loop knots is that it is quite easy to adjust, so that an anchor of a number of parts can easily be equalised.

Note that the load bearing part of the knot should be located as close to the spine of the carabiner as possible. Otherwise you are putting additional strain on the carabiner.

Clove hitch
Form a loop in the rope as shown Clove hitch - slide 1
Form a second loop next to the first in the same direction as the first. Note that in this case, the loop on the right is in front of the loop on the left. Clove hitch - slide 2
Pass the front loop behind the back loop. Clove hitch - slide 3
Clip a carabiner through the two loops. Clove hitch - slide 4
Pull tight and set the knot. Note that ideally, the load-bearing strand of rope should be closest to the spine of the carabiner, as shown. Clove hitch - slide 5