A quote from the opening post on the Riparium Plant List
thread that should help describe ripariums.
Originally Posted by AquaAurora
A Riparium can be most simply defined as keeping plant leaves/stems emersed (above water) while roots are immersed (below water) in the aquarium. This can be done via raft, planter basket, shower caddies, stuffed in HOB or attached to hardscape/decor to achieve the same effect, as well as just left leaning against the side of the tank/sticking through an opening in a lid or if tall enough planting the base of the plant in the aquarium substrate (edit: to clarify I am referring to Lucky bamboo here with stocks below water but stems above).
In a high humidity riparium many aquatic plants can be grown this way, but a lot of house hold and other plants also work with this style and don't need such high humidity. Its a great way to boost nitrate absorption and add more life and color above/around the tank as well as giving more hiding places in the roots for fauna. The downside would be the obvious shade created by these emersed plants means less light for immersed plants below them, but some work with lighting types (like submersible LEDs) or setting up lights at an angle can help get around this.
As for lighting it depends on what plants you are using-same deal as with aquatic plants. Pothos for example is a simple easy low light plant, while I've found Ruellia brittoniana 'Katie' does better in medium or high light, in low light Ruellia lost its lower leaves very quickly on my riparium.
Method of planting can vary. Most commonly plants are anchored in a foam media place at the top of HOB filters, or in plastic shower caddie style 'planters'. But there are people who have made over the tank sump systems with flower boxes planted with riparium plants as well.. and I recall someone had acrylic planter box build for their tank (back of tank sump). There is no real wrong way to plan as long as: you use aquarium safe materials (nothing that breaks down, contains harmful chemicals, or is unsafe metal (not stainless steel)), as you ensure the plants leaves stay above water.
There are no specific rules for substrate, I personally use expanded clay media which is commonly used in hydroponics and aquaponics-aquaponics is very similar to ripariums though typically involving edible plants and keeping the plants and their roots out of reach of the fish (to avoid the being eaten). The clay media is very light weight and wicks up moisture so you don't have to be too careful about keeping water level at max. Plenty of people use gravel and I've seen some use enriched substrates like aquasoil. Since I use an inert substrate I dose liquid ferts in the tank (phosphorous, iron, potassium, and seachem flourish). Because these plants have access to plentiful co2 you do not need to inject co2 into the tank or use a co2 liquid substitute, they don't need it. If you are say using a large planter box where all the plants roots can share the same substrate you could use roots tags or consider a soil base with a cap (would not personally recommend for the shower caddies as these had slits on the bottom-soil would get out, ). Whatever you sue for ferts make sure its aquarium safe fertilizers, some garden ferts may harm fish, inverts, and your filters beneficial bacteria.
As stated above Venus fly trap (which according to someone I know that grows them in a closet (I know sounds odd) are high light plants and) not good candidates for a riparium. Standard house plants (excluding cacti, succulents, and coniferous plants) are a good place to start, but anything that needs a dormant/winter period is not a good idea unless you are willing to take the plant off the riparium and place in garage/outside for the winter.
I keep my water line near the top of the tank but evaporation brings it down quickly so I have to top off the riparium tanks 1-3xs a week. I don't know much about your fish but knowing if they are jumpers or not would be important to answer how low you keep your water level.