I just learned the hard way of starting an aquarium. But this is what I have learned and has resulted in a beautiful aquarium.
I have a 30 gallon vertical.
I started with a good substrate, I didnt go to the store and buy the dirt. I went to the local creek bed. Got a pale of silt and baked it in the oven until sterile.
I placed coarse gravel over the substrate in the back and fine sand in front.
I bought a canopy lighting that has 65 wtt upgradable to 130 watts.
I placed all my larger plants in little clay pots and planted them in the background.
set up a DIY CO2
for fertilizer I use a liquid cow manure, but be careful using cow manure, it will cause algae if you use to much.
Once my aquarium has settled down, (cycled) I keep my hands out of it.
also, plant selection. This is tricky because what you buy at petco is usually a native pond plant around my area of living. You can never be sure what is truly an underwater plant or shore plant. This is how I learned, if you hold the plant by the stem and it stand erect on its own, then you have a shore plant, however, if it flops over and needs support, then chances are you have a true aquatic plant.
I don't over feed the fish, only give them enough to finish in one minute.
If you have what appears to be dark algae, chances are those are diatoms. Usually low lighting causes that and is normal for all aquariums when starting one, however, take a gentle tooth brush and remove off the leaves of the plant. Once you're aquarium cycles you shouldnt have diatoms that often.
Good luck, but be forwarned, having a beautiful aquarium is additive, I can spend all day sitting in front of it. My plants grow at least 2 to 3 inches a day. I have actually started holding tanks in the backyard for all the additional plant growth and cuttings. Now I have moved a lot of my fish to those tanks also, since they breed like rabbits.