Some general tips to keep in mind:
100 x 100 feet as a general guideline
Try to minimize slope of the site.
Set up so pilot may approach into wind,
Be aware and have approach clear of obstacles (e.g. powerlines )
Prepare the landing surface area (wet dirt to avoid brown out, or stomp snow to avoid white out)
Marking- cones or strobes may be used. If using chemical light (only orange, red, white can be seen by night vision goggles)
Horseshoe pattern facing wind for the markers like so:
A light, piece of light clothing, or flare is placed at each corner of the HLZ. A fifth light, flare, or piece of light clothing is placed 5 to 10 m outside the square directly upwind, showing the pilot the wind direction. All lights, flares, or clothing should be firmly attached to the ground to prevent them from being blown away by rotor wash.