Night Nav is a good skill as it helps you improve your general nav skills. But if you are going to practice, make sure you leave a route card with someone you trust and give them a return time plus an action plan if you fail to return. Also carry adequate kit "Just In Case".
As for the practical aspect:
A few good points have been raised above, such as hand railing or linear features. Pacing is essential and a good thing to have in your knowledge bank. Clickers, Beads and knotted string are good techniques for keeping count, as is double counting i.e. Instead of counting every step, count only your left stride (or right, remembering to half your paces to the 100m) smaller numbers are easier to work with especially when your cold and wet.
Another thing to be wary of in poor light conditions and mist/fog, is navigational drift or bent, which is exaggerated in these conditions. Each person is different and the distance / direction they will drift is unique to them. To check it out, first get a friend to help you so you don't walk into a wall etc by accident, pick a point in the distance and orient yourself to walk towards it, put on a blindfold and walk in the direction of your chosen target. Your friend should be close by to stop you bumping into stuff, but shouldn't offer any directional aid. After you have paced out your 100m check out how far you have drifted of course, something to be aware of.
Another point when navigating in poor light is to shorten the distance between you checkpoints or way markers; this lessens the chance of errors.
When making up your route cards for a night nav, try and select features that will be visible at night such as skylined objects etc. Always check contours and relief, as this is a great aid, and if you expect to be walking uphill but are actually walking down, you could be going the wrong way!
Hope these points were of use, had to use them myself a few times and they do work - honest