DEET works! Stronger the better, but don't use on small kids. Turns plastics to goo, especially bikini buckles :-{). Pump sprays rather than aerosols are more controllable.
Works by evaporation, so top up 4-6 hourly.
Wear long sleeves & trousers after 4pm
DEET-soaked nets & wristbands are good
Thiamine tablets (Benerva) are useful at 100 - 300mg daily, but make you smell worse than fresh DEET.
Citronella oil is now so far down the list that you're not allowed to claim repellent action on the bottle.
Autan works better in trials than real life (as if life's not a trial)
And yes, the buggers do go for tourists more than locals. A bit of research here might be the next step forward, if any drug company policymakers are reading.