Which side to turn in? Even experienced pilots may find out that they have turned to the wrong side sometimes. However there are also situations where the pilot has no choice about the side turn. This happens for example if other gliders are already turning in this thermal, or if in the mountains the distance to the ridge allows only one direction.
After finding a thermal and turning in, it depends on several facts how well centered the first circle will be:
Where was the thermal hit?The pilot has no influence on where to hit a thermal,it is plain luck,.
When to start turning? It is a matter of experience and also of some luck to turn in at the right time.