Removing the dying (yellow) leaves will help your buds. You can save and cure these leaves as they do have THC value. Once the plant enters flowering mode you need to focus on nutrients – buds love phosphorous so you can feed with a 10-30-10 mixture (nitrogen-phosphorous-potassium). You can boost with some extra potassium towards the end of the flowering cycle. Remember to keep the PH balanced throughout – ideally 6 for soil or just under for other mediums ( around 5.5). Nutrients aren’t absorbed properly if the PH is not balanced.
If you are looking to increase your potency in the yield you can pinch or top the main cola/shoot during vegetation to render additional colas. Both techniques can be applied when the plant has 4 to 5 nodes. Pinching will yield 2 – 4 colas, topping will yield 2 colas.
Pinching: Pinch the newest formed leaves (top growth) at the top of the main cola (you don’t have to break them off but it is ok if they are removed)
Topping: The main cola is removed (cut) right above the second leaves (node) from the top
** These techniques render different results and can be used throughout the growth cycle but the plant has to recover before it is applied a second, third, fourth time … etc.