Personally I would work on getting a consistent and stable grow space in regards to light intensity, temperature, humidity, and ventilation. After that you can really see what changes to nutrients and training can do for your yields. I tried to do topping and LST while going through my first run, of 5 different strains, and it was more than a bit hectic and I learned little about training and can't really say how, or if, anything I did improved my yield.