A free shuttle bus operates between two every 20 min. While the terminals share the same runways, connecting between the two requires a massive detour via a nearby highway, so allow plenty of time to connect.
You can find prepaid taxi booths at the airport. They are operated under the direct supervision of the traffic police. It helps to avert over-charging, refusal, misbehaviour or harassment by the drivers. You simply go there, tell where you want to go, and then a duly signed receipt indicating the taxi number, destination, service charges, and the fare will be given to you.