Having the right Equipment
» An adapted habitat, like a tank
Cages are not recommended, they can't hold a lot of bedding and it picks up everywhere. In addition, gerbils tend to chew the bars unhealthily, which is noisy, and can also cause injury to the nose.
A MINIMUM of 10 gallons per gerbil is recommended, so a 20 gallon vivarium is the bare minimum. The ideal is a 40 gallon for a pair.
Unfortunately, in Quebec, we do not have a lot of decent gerbil food. Most "gerbil" foods are often mixed for hamsters, which have different needs. If you can find it, the 2014 Teklad is the best balanced for pet gerbils. Next is Oxbow's Garden Select for Rats, which is available at most pet stores. There are also some mixes, but they are often poorly balanced. You can also make your own homemade blend, there are several good recipes on the Internet.
» Cardboard to chew
Toilet paper rolls, paper towels, kleenex boxes (without the plastic), even tissues (without products!) can be good ideas for things to offer for your gerbils to chew. Confidential papers to get rid of? Leave them to your gerbils, they will nest with!
» Lots of bedding
Corncob is the most absorbent, but does not hold well enough for . Aspen is ideal in this aspect, but is less absorbent. My thing is to mix both for optimal effect. Avoid paper (like newspaper), knowing that it absorbs very little, but bedding like "Fresh'n'comfy" can do. Do not be afraid to put a lot, we talk about an 8 to 10 inches of litter to be able to dig long tunnels.
» Water bottle
Here you have the choice between a bowl or a bottle. My recommendation will always be the bottle for reasons of simplicity but also cleanliness. Bowls can be knocked over or filled with bedding. Bottles are more reliable and limit the risk of damage if they are well placed. A practical, but often overlooked, accessory is the bottle brush. You can go get a brush for water fountain (in the dogs/cats departments, I personally use CatIt's). Stagnant water can mix with dust and create algae/bacteria, so it is important to clean the bottle at least once a week.
Gerbils need a sand bath from time to time to wash. Their hair should not be wet, like chinchillas (although it is less damaging for them). Be sure to take sand, not dust. The dust is too fine and can cause breathing problems. You can leave it permanently but your gerbils will surely end up burying it and/or pooping in it.
» Toys and Hideouts
You can give coconut hideouts, wooden bridges, terracotta pots and things like that. Remember that gerbils eat up just about everything in their path, so you will probably have to buy them periodically. Avoid anything that is fibrous, which is very dangerous for them, and plastic stuff that can cause blockages if ingested. If you offer a wheel, take one at least 10 inches wide (smaller is dangerous for their backs) and full surfaced (like a Silence Spinner).