Alright, I'll try to cover everything one thing at a time.
Substrate - Any type of substrate will work. In my 55g I use plain sand but am planning on moving up to dirted when I upgrade to a larger tank. Regardless of what type of fertilizer you use you will need to use root tabs but the specific plant substrates will make it a little easier to get the nutrients to your rooting plants. A lot of people buy commercial root tabs for their plants which are sub par or else they make their own root tabs which is a far more effective option. The home made root tabs that I use cost about $0.004 each and last 2 months or so.
Light - This is the most important thing as it will determine everything you do with your tank. Low light is the least maintenance and usually involves a single t8 bulb or low end LED fixture. With low light you won't necessarily need fertilizers or carbon for your plants even though it can help them grow a little faster. Moving up to medium to high light levels it is highly recommended that fertilizers get added to the aquarium as well as a carbon source.
Fertilizers - For low light tanks the liquid seachem ferts are a viable choice. They don't offer a whole lot of nutrients but that's just fine when you have slow growing plants. At medium and high light it is fairly standard to use dry ferts on a specific dosing regimen. The dry ferts are commonly bought from
Green Leaf Aquariums and are dosed according to the Estimative Index (EI) or the Perpetual Preservation System (PPS - Pro)
Carbon - There are only 2 real source of carbon supplementation when it comes to planted tanks. Again, this isn't particularly necessary in a low light tank although it will help. The first is Glutaraldehyde. This is commonly bought in the form of Excel which is a Seachem product or Metricide 14 day sterilizing solution. They are basically the same thing except that the metricide is 2x as strong so you only need to dose half as much as well as being WAY cheaper. Start out with 1ml / 10g of excel or 1ml / 20g of metricide and work your way up from there. You can safely go up to 1ml / 1 gallon or 1ml / 2 gallon respectively but that build up needs to be slow so as not to shock your system.
Plant selection -
Low light plant list -
Excellent List of Low Light Plants
After that you will have to do some research about some plants you want and figure out the light level from there.
Algae - Algae tends to grow when there is an imbalance of light, ferts, and carbon in the aquarium. The most common cause is improper amount of carbon.
Like was said previously, it's easier to start out with a low light system and learn that way than it is to jump straight in at higher light levels (which is what I did)
