This is very basic stuff but people still continue to take a leap of faith when they don't have sufficient airspeed. Think about where to lay out not just depending upon available space and where others are, but also think about the conditions and how they might be by the time you actually launch.
The lift changes throughout the thermic day on our principal launch site. The site faces NW so the technique of flying it is somewhat different than you would follow on a southerly facing mountain. This can catch many pilots out and find them struggling early in the day.
Sometimes conditions look good at the launch, even though the forecast may be for strong winds. If you have not checked the forecast and go just on what you see at take off you may be in for a nasty surprise.
There are a few sites in the world where topographical shielding from winds allows us to fly when perhaps we should not. There are many factors which may lead this shielding to break down.
At Peña Negra it it can look flyable against all expectations with a strong E forecast. THis tutorial examines why it is possible and the reasons why it breaks down and normally leads to a white knuckle ride for those who had launched into nice conditions. There is a fair bit of weather terminology and reference to SkewT diagrams. However, it has been made as simple as possible to make the reasoning clear.