For your mountain bike to perform optimally, by moving faster, for instance, it is necessary that the steps mentioned below are properly followed:
The first step would be to keep your bike clean. A clean bike would undoubtedly be a fast one, as mud and other substances which are likely to stain your bike, would be frequently cleaned. In the long run, you would realize that your bike becomes more efficient, and money would be saved, instead of spending on replacing dysfunctional parts. Always ensure that your bike is not too dirty, as it would be more difficult to clean.
Next step is to lube the chain. A chain which is well-lubed chain would ensure that cycling is made more efficient. Hence, none of your efforts would be wasted because of mechanical ineptitude. This would also reduce the quantity of mud which the chain could absorb during rides.
Also, lowering the front end, is another effective way to make your mountain bike move faster. If there are spacers placed between the headset and the stem, it would be quite easy, as you would just need to take out the fork and spacer, replace the stem and put the spacers back. It is advised that a great deal of care is exercised when doing this because this new position might be alien to the body. So, ensure your flexibility is in place, in order to avert injury.
In addition to this, ensure that the height of your saddle is correct. A saddle with the right height would reduce the chances of having injuries and being uncomfortable. However, if the reverse is the case, it could induce a loss in efficiency, and reduction in the power passing transmitted to the pedals. The ideal height of your saddle can be gotten by subtracting 10cm from your inseam length.
Likewise, check if the pedal tension is right. If your pedal tension is not properly adjusted, you might be using your toe, and this would definitely make you uncomfortable. Pedal systems come in different varieties, hence, the method of adjustment would be different. However, it is up to you to find out what works best for your own.
Furthermore, checking the pressure in your tire is something which should not be skipped. If your tires are too soft, it could reduce your speed, and you could be at the risk of having a punctured tire.
Also, check your gears to make sure that they are suitably adjusted. If they are not in shape, they have the tendency of spoiling the fun during riding. You could spend more time than usual for a trip which would normally not waste time.
On a concluding note, check your brakes to ensure that they are appropriately adjusted. Coming to an abrupt or planned stop does not necessarily mean that you ride faster. However, if you can make sure that your brakes are in a good shape, you can be sure to ride faster without having fears of a brake failure.