Before starting with the construction of a Carnivorous Plants Terrarium, the below rules should be considered:

- Decide if the Terrarium will take place in or outside. 
Indoor Terrarium is suitable for tropical plants which require quite stable temperature, long photoperiod and don't need winter dormancy.  Outdoor Terrarium is suitable for plants which require seasonal changes of temperature, photoperiod and  winter dormancy. Growing hardy plants ( or tropical ) in the wrong environment means to consider them annual plants.
So when you decide to start, think about the plants you'd like to grow. Obviously, if you live in temperate areas with cool
winter and warm Summer (mediterranean like), you may decide to create a mixed cultivation which may include hardy
and tropical plants.
For example, here (Genoa - Italy -  N44° 26'  E8° 48'  200m asl ), winter temperature usually don't  drop  under 0°C
and summer temperature don't rise over 30°C, on the other hand  humidity changes from 15% to 90%. In this case it is possible to grow outdoor a wide variety of plants as the common and easy Drosera capensis and Drosera capensis var. alba, Drosera comunis, Drosera spathulata, Drosera binata, Drosera dielsiana, Drosera burmannii, Pygmy sundews, Drosera adelae. Hardy  drosera as  the american native Drosera filiformis and the northern Drosera rotundifolia and hardy pinguicula as Pinguicula vulgaris and so on.
Other Carnivorous Plants take place in the  same Terrarium as  the australian Cephalotus follicularis, the attactive
Dionaea muscipula, Sarracenia purpurea, , Heliamphora heterodoxa, Heliamphora nutans, Pinguicula x weser,
Pinguicula primuliflora, Utricularia sandersonii etc.

Please note that the best results can be achieved if  plants start from seed. For example, a northern plant  born in terrarium or greenhouse has more chance to survive then  plants collected in the Wild.

-Assign a  place to the Terrarium. A good place for an indoor Terrarium is far from heating and direct sunlight, avoid
also  room with poor air change, dust and smoke. Like Aquarium, Terrarium is an ornament if set correctly.
For  outdoor Terrarium good place could be a porch. It's important that rain never sprinkle any surface, remember that
electrical part are present in the tank. Also for outdoor Terrarium is important that sunlight never hit against  the glasses causing leaf burn.