Cymbals are usually recorded with a mike for the hi hat and two mikes for the over head to capture the rest of the cymbals (crash, ride, etc).
The sound of the cymbals is thin and empty in term of harmonic content, so the final result depends a lot on the mike used and its position, this is very true for the hi hat, if you want to get a a raw and metal sound place the mike on the outside of the hat, if you want a thinner and percussive sound place the mike close to the bell of the hi hat.
While mixing you don't have to do much, usually you have to cut below 300-400Hz (it depends on the sound you want) and boos by 3-4db above 8000-10000Hz.
Use a compressor if necessary to enhance the percussive character of the instrument by using a slow attack (15-20ms) and a short release (5ms), with a ratio of 4-5.
These tips are true both for the hi hat and for the over head, but usually on the overhead you cut more, up to 500-700Hz.
an important thing to remember is not to put cymbals to high in the mix since they are not the main instrument of the drum, this part is to be played by the snare and the kick.