Siting the shelter properly is important.
Wind direction has a very large effect on your comfort, if you are going to be near large areas of water (the sea or a lake) remeber that the wind direction may change to be the total opposite later on at night or in the evening.
You need to have water within a reasonable distance, but remeber where there is water there are insects and you will not want to be eaten alive.
Don't set it up on a ridge as ridges tend to be more exposed to the elements (wind and rain) in some places (the jungle for instance) you may find that they are prone to deadfall areas as well.
Don't set it up in the lower ground as troughs fill with cold air of a night and if it rains heavilly you may find it turning into a watercourse.
If the roof is at a steep angle it will shed water faster and better, but reduces the sleeping area by making it narrower and requires a lot more debris to stack up to cover it, but at the same time if it is too shallow it will not shed water so quickly and the debris will become sodden and possibly leak (as well as becoming heavy and putting more stress on the shelter itself). Look towards a 45 to 60 degree angle (more the latter)
Make a good bed using bracken and the likes and it will insulate you very well.
Use your jackets turned inside out to collect the debris, it will allow you to collect more a lot faster and reduces the amount of trips you will make.
Oh and make sure it is long enough.
All the best with the night out