I'm pretty sure the rear has to be locked before the front will lock on a Rubi unless the switches have been tinkered with. 99% positive on that one, but I don't have a Rubi so...
As far as techniques go, experience is the best teacher. Get out and have some fun. But like 03Rubi said, don't lock it up on pavement - that's just asking for problems.
General techniques: There is no such thing as too slow.
Best strategies: Don't get stuck and keep the wheels on the ground.