I guess the first thing is how the sunlight gets into the tank. You don't want full sun getting into the back of the tank. In nature, there is no 'back or side of tank'. A part from midday, light enters obliquely. This light can never shine directly on lower parts of the column. Thus, if you don't regulate light with Venetians, use several strips of shade cloth. More layers (getting darker) as you go down so that less light reaches the lower column through the glass.
In my current tank I use a three D background.
People seem to think only certain fish and shrimp eat algae. Not so. There are many other critters from microscopic to almost visible that enjoy this little dish. The issue is that people go to the lfs and buy fish, crustacea, plants etc, but where to buy the other hundreds of organisms? I scoop the top layer of a 20 year old open rain water storage system now and again and dump that into my tank. I can see mosquito larvae and some smaller critters in there but there are millions of others I can't see.
Why is it that algae grow on 'sick' or old leaves but not on healthy? And why mainly on the edges. I think that healthy aquatic plants have a mechanism to keep algae off the production areas. Healthy plants don't just out-compete algae, IMO, they kill it.
I once cleared BBA by simply adding a little potassium to the tank. The plants picked up and the algae went away. Although this was an artificially lit tank.
Then there is the UV component of sunlight. What effect does this have on the upper layers of the column? Glass inhibits shorter UV wavelengths so I open the window and remove the lids. (I have to be careful here as I have 'jumpers' in the tank.) We assume that only certain small areas of the spectra are good for tanks, I don't think so, but unless you have small portable fusion reactor you're stuck with artificial light.
Balance is key. If you don't have the hundreds of flora species the balance is harder to maintain long term so people end up fiddling around with phosphate levels, lighting, CO2, nutrients etc. Very frustrating.
I only have a few plant species in this tank. Ambulia, Wisteria, Echinodorus etc. Nothing special. The first two grow very very rapidly and help me export excess nutrients out. I need bushy areas for some fish to spawn or hide. Other than that it's a blackwater tank with more dead wood and leaves than plants.