At this point a lot of information is stored in your short-term memory. However, it will become lost and confused very quickly. If you are using buildings as landmarks, note your exact position. If you are using distant hills, an error of a hundred meters won't hurt. However, using stars as landmarks means that an error of a kilometer or two in your position will be perfectly acceptable.
Stars make the best reference points.
Note the date and time. Write down what you remember as soon as possible. Make sketches showing positions and directions. Include the landmarks. A couple of reports of this kind can make a big difference.