In my experience I began producing fluffy. Lighting, Nutes, Air Flow, Temperature, & Humidity were neglected.
As I moved forward and developed my knowledge of this beneficial plant and its environmental requirements, I became aware of Temperatures and Air Flow.
I designed a grow room with Air Flow in mind. I still ended up with wispy/fluffy bud that had no weight or amazing medicinal grade.
I soon stumbled on a 1.2kW 6 plant grow that ended up the same. This person, pretty much like my first time, neglected certain aspects and hoped for the best.
Together we pondered over the idea of increasing bud density. Over time we both began to take more control of the plant environment. Gradually, over the timescale of tens of months and perpetual growing we started to get denser and higher yields.
I tell you what was done.
The triplets: Air Flow, Temperature, & Humidity
Crucial! Fresh Air and the removal of stale air is very necessary. This flow of good quality Air is a must and should not be skimped on. With adequate Air flow, one will seldom find many problems with Temperature and Humidity. If Temperature becomes and issue, then having a switched Exhaust can help keep Temperatures up. Or if the Temperatures are too high, then either more fresh air or an Air Cooling device is required.
In my experience, sufficient Exhaust was usually enough for 3000W of HPS in a room with a window open that neutralized the vacuum created by filtered 10" Extraction ducted to a chimney.
Nutrients. Know what your plants require. Learn each stage of the plants development. Understand why a plant requires certain elements at particular stages of its growth. Understand the physical traits of common deficiency. Over watering; Under watering; Potassium Lack; Over Nitrogen etc. I'm not saying one has to learn absolutely everything, but a little knowledge helps to counteract deficiencies as they arise in their early stages as oppose to waiting until your plant is stressing out.
Knowing what your plant food does for your plant is good information. Knowing what certain amendments to your nutrient solution can do for your plants is also beneficial. Much of this is trial and error. You can ask many people advice on feeding, and they do what is best for them personally. Who's to say it will work in someone else's Grow under different conditions? *shruggs*... Know your Nutes!
Lighting. I began my hobby with 250W hps & mh. But with all other aspects not in check, I could have ran 1000W and still not gotten anything better than I did. Using a lot of light is something I recommend to those who has the ability to address all of the point I raised above as a single unit.
Loose Vs Tight.. Well a friend just harvested some AK47 which is very very Loose. They grew in hydro under 'newbie' conditions. I am growing the same strain under very good conditions in comparison and my 40 day in to bloom AK47s are rock hard and still have a way to go. Environment and knowledge and access to resources the plant requires is all I provide that is different.
Sorry for the long post.