Mostly I fly gliders, but just like powered a/c, the most critical time is the first few hundred feet where the towplane engine can fail or the rope can break when landing in the trees as slow as you can is about all you can do.
Twin turboprops blasting through a busy thermal can get your attention, but at least I have a chute -- can't say I'm blameless on the other side as I once found myself flying a C-172 through a well populated area of lift
The best way to keep yourself safe is to fly the same as you would for your flight test. Get the wx and NOTAMs, calculate your fuel and w/b, do a proper preflight including verifying adequacy of proposed runways vs. load and density altitude, use a checklist... and you will have eliminated many of the popular accident causes.