The worst form (as far as potential threats to safety) of turbulence to encounter is windshear. Please see our responses there. You posted the topic
The second form of turbulence that can have implications is Wake turbulence. Wake turbulence off an aircraft is like the wake from a boat--from an aircraft though, it's generated by wingtip votices. The bigger the aircraft, the bigger the wake it will generate. Jumbos and 757s generate the most formidable wakes. Wakes will usually drift below the level of the aircraft's flight path and drift with the wind. Thus, if you can feasibly lift off at an earlier point and outclimb the path of the departing traffic, you should be okay. That's easier said than done, and in most cases, wake is just a temorary rock of the boat through which easy recovery can be made. Tower will give an advisory, "Midex 901 cleared for take off, fly runway heading, caution wake turbulence, departing DC-10"
On landing in wake, if you are much smaller, try to touch down at a point aft of the preceding plane's touchdown point as the wake turbulence will end where the generating aircraft's flight path ends or touch down point occurs.