The main concept of LST (Low-stress training) is to shape the canopy and stems in a way that will maximise yield, for example, the upper canopy can have fan leaves that shade bud producing stems. LST also allows the plant to be more open, giving each branch more growing room and a chance to branch further.
LST should be applied as soon as the plant has 2 nodes as this is when it is flexible and not brittle. One of the best options with LST is to try to make the main stem grow sideways so that most of the branches aren't in the shadow of the main canopy as they would be if the canopy is directly above.
It may be necessary to adjust your LST every day or every two days when the plant is growing quickly
LST techniques
Pining stems down
Here paper clips have been used to pin the stem down as it grew. This greatly reduces the height of the plant. This method is more suitable to more compact mediums like soil as pins require some friction to hold the stem. Pinning should start as soon as there is a long enough stem to pin. You can grow a seedling in low light to increase the stem stretching in the seedling phase. This can increase the inter-nodal distance giving your branches more space later on in flowering.
Ponytailing
Ponytailing is the process of tying leaves up in a bunch together to remove the shade they create. This also leads to the ponytailed stem receiving less light and stretching more as a result. This can be done with small cable ties or paper clips
Defoilating
Simply the process of removing access leaves. If there are too many leaves the humidity can become too high and also fan leaves that do not create buds can shade other branches that will bear buds. Take care to not prune when the plant is a few weeks into flowering as this will negatively impact yield.