The aquarium water
The water in both African lakes is quite hard and even though it is not necessary to imitate the exacts values in the aquarium, it is recommended to test the tap water in your area for GH, KH and PH and if necessary raise them.

For Malawi cichlids I would recommend:
PH between 7 and 8,
GH 7 or higher,
KH 10-12
Temperature 25 - 27 degrees Celsius

For Tanganyika:
PH 8 - 8.3
GH 25
KH 15
Temperature 25 - 27 degrees Celsius

Malawi Ciclids are, generally speaking more tolerant when it comes to the hardness of the water, but for my Tanganyika tanks I try to come as close as possible to their natural environment. Remember when adjusting the values of the aquarium water that you have to change one third of the water once a week. The 'new' water should be prepared properly before adding it to the aquarium. If you have tap water that is near the recommended values I would not try to raise it, it makes the regular water change more easy, in my area I keep the Malawi cichlids at ph 7, GH 5 and KH 8 without any problems.

Cichlids are rather large eaters and produce a lot of waste products, a good filtering system is needed. The easiest way is to use an external pot filter, the larger it's filtering capacity the better.

African cichlids tank basics
The cichlids from the great lakes need a similar tank setup, a large tank, even for the smaller species, from 60 gallons ( about 200 liters ) and up is an absolute minimum. Create some rock formations, preferably separated by some plants or open areas, this makes building up territories more easy and reduces stress. I prefer to use sand in my tanks instead of gravel, it makes foraging for food and digging more easy for the fish. Put some large plants in the tank, maybe some floating ones as well and your tank is ready to stabilize. This means letting your tank run, without fish, for about two weeks. The plants can grow and bacteria will develop, in the tank and the filter substrate. There have been a lot of discussion among aquarium hobbyists if a stabilizing period is really needed, but I would advise to use one for at least two weeks.

Xenotilapia sima

The fish community
For both African cichlid groups it is very important to choose the right species to develop an harmonious community in the aquarium. Here are a few guidelines in choosing your cichlid species:

1) Only combine fish that have the same feeding demands. Both lakes have real food specialist. Tropeus species are a good example, they are mainly herbivorous fish, they feed on algae in their natural environment. If these fish are kept with other carnivorous fish, they will consume their food as well, but they are not capable of digesting it very well. In the long run, these Trophous species will die from diseases. Some of the Mbunas from lake Malawi are also mainly herbivorous, but these cichlids are much more tolerant when in comes to their diet.

2) Try to combine fish from different niches ( a niche is the main dwelling place of the fish, like rocks, open water or sand )and breeding behavior. This will reduce competition along the fish in finding the best breeding spots and in defending their territory.

3) add all the fish at once, this is an important one. Never add fish to an established community, they will be hunted by all, have a lot of stress and could easily die. The only exception on this rule are the big cichlids, they can defend themselves enough.

4) When it comes to Malawi cichlids it is best to overcrowd your tank a bit, it makes focusing on a few less dominant fish less a problem.

Here are some examples of African cichlid community tanks that worked very well for me in a 400 liter tank, about 105 gallons.

Malawi community
Aulonocara ( peacock Cichlid ) : 1 male, two or three females.
Labidochromis caeruleus ( yellow ) : 1 male, two females
Pseudotropheus zebra : 1 male, two or three females.
Labeotropheus trewavasae : 1 male, two or three females.

Tanganyika community
Neolamprologus brichardi or Neolamprologus pulcher : one couple
Xenotilapia sima : a group of 5 fish ( Schooling Fish )
Neolamprologus leleupi or Julidochromis transcriptus : one couple
Cyprichromis leptosoma : a group of 5 to 7 ( Schooling Fish )

or
Cyprichromis leptosoma : a group of 5 to 7 ( Schooling Fish )
Lamprologus multifasciatus in a small group ( two couples ) or Lamprologus ocellatus ( never both in one tank )
Altolamprologus calvus : one couple
Julidochromis marlieri : one couple

Food
The African cichlids I mentioned as an example are all carnivorous or at least have a good tolerance level when it comes to their diet. I feed my fish red bloodworms, artemia, and a cichlid mix ( all frozen blister packages ) I never use flakes or other dry food for my African cichlids, but there are special dry foods and flakes your could try. But I would not recommend to use it as your main food source.