Recently there have been a number of people complaining about their clutches and/or crunching while going into gear.
These complaints can be solved with just a few checks & adjustments.
First of all you have to make sure your gearbox oil is fresh. The number of people who do not even consider this is shockingly bad.
There are many brands out there claiming to be the best, personally I use Honda MTF III.
Another vastly overlooked fluid is the clutch fluid itself. This is easily changed, the hardest part will be getting the right amount of access to the slave cylinder.
These both need to be addressed before you adjust the clutch.
There is no point adjusting the the clutch if you're pushing against air and dirt.
To adjust the clutch you only need a 12mm open-ended spanner.
As you can see in the picture below the top of the clutch pedal pushes on a rod in the clutch master cylinder through the firewall.
1) Loosen the 12mm locking nut (clockwise - looking at the firewall from inside the car).
2) Rotate the rod to adjust the clutch
3) Push against the clutch pedal with your hand and re-tighten the locking nut.
Depending on the result you're after depends on what way you turn the rod - experiment.
If you are experiencing a slight crunch at high revs there is a high chance the clutch is not disengaging fully; or, if your biting point is too low to the floor you need to lengthen the rod to remove the free-play.
Longer rod: moves biting point up.
Shorter rod: moves biting point down.
I must stress, if you are having problems with a low biting point you need to first change the clutch fluid.
*I have read this over to myself many times and am still not completely satisfied. I will continue to edit this post with any information I have been too vague on or have completely missed out.*