For a thriving planted tank, strength and spread matters. A low light tank is easier to maintain, but is more suited to shade-plants that generally have less color.
The majority of vibrantly colored plants require strong lighting, and the right color spectrum to reveal their best form. Read more here.
Fish and plants both have specific preferences in terms of water parameters (pH, KH, GH etc.) temperature and flow. The important thing here is to acknowledge that one size does not fit all.
One basic distinction is between softwater tanks (loosely 'lower pH and KH') and hardwater tanks. Read more here.
A tank without a filter / pump is like a stagnant pool. While it is possible to have life in such an environment, having a good filtration system opens up far more possibilities.
Sufficient filtration strength and capacity is essential to support a lively fish and plant population. Design matters. In general, canisters perform alot better than hang-on-back options.
Choose your workout! Certain setups can require little maintenance, such as tanks with low light, lots of slow growing plants and fewer fish.
More lively, interesting aquascapes generally require alot more regular involvement. Carpets for example are like terrestrial lawns- they take consistent work to maintain :)
Right pairing matters. Many omnivores and will eat /damage plants. Even popular 'algae-eaters' like the Amano shrimp and some Plecos create noticeable holes in leaves.
In a tank with a heavy fish community and higher nitrogenous waste, some plants are far more susceptible to algae, so choice is important.
While an aquarium looks naturalistic, it is not ecologically complete and fish waste and organic detritus do not provide all the nutrition required for healthy plant growth.
Read more about the macro and micro nutrients that plants need here.
CO2 injection, while seemingly artificial, is necessary to replicate the instances in nature where lush, colorful plants thrive in CO2-elevated environments.
If you are serious about growing plants, a proper CO2 injection system (not 'liquid CO2') is a necessary investment. More here.
Achieving a thriving planted aquarium can take a fair amount of research and experimentation.
The 2Hr Way is a proven approach used by thousands of aquarists to fast-track that journey.