Bug hotels are great fun for the family to build and can be as varied in shape and size as you want them to be. The key thing to consider is which species you are building them for, as that will decide what you make them from and where you position them.
Insects such as some solitary bees and lace wings need dry hollow stemmed material such as bamboo, dried reed stalks or cardboard tubes of various sizes enclosed in a wooden frame and positioned in a sheltered dry sunny place such as a garden fence or garden shed wall. Marc Carlton’s excellent website provides lots of information on this.
Beetles and Bugs need looser damp material such as leaves, straw, bark, rotting wood and broken flowerpots packed into a framework such as a stack of old untreated pallet boards or an old cupboard with its doors removed. For best results place the structure in a low, cool, moist location out of direct sun.
Bumblebees like nothing better than a compost heap or an old mouse nest in a sheltered bank. Failing that then an old biscuit tin or wooden box with a three-centimeter entrance hole made in it makes a good compost heap substitute for them. Pack the box with a mixture of wood shavings, moss, straw or dry grass and place it in a sheltered sunny area and slightly raised off the ground to prevent the box from flooding in poor weather.