Well, ok it's not my first -- I had one a a kid, but that was back when we were told to take it apart and clean it every month. Needless to say, the fish died.
Below is my first planted tank after about 45 days. As you can see it is not going great, but not too bad either. The water is murky, brown algae is a problem, and some leaves are yellowing. I just haven't quite got the nack of it.
Here's whats going on with it:
29 Gallon Tank
Aquaclear 30 - two sponges and biomax
Stealth 150 heater with water temp of 74
DIY CO2 going into a ladder diffusor
55W A H Supply retrofitted into a PetSmart bought hood.
R/O water but tank readings are 6.6 Ph, 5Kh, and 5Gh
Blackwater extract added, Seachem micro fert added
Fish still alive (for now): 12 Cardinals, 3 Cory Pandas, 2 Sparkling Gouramies, 2 endlers livebearers, and 2 Ottos.
Plants that I can name: Anubias, Riccia, Java moss and fern, Cabomba, mondo grass, Lotus, dwarf hairgrass, two swords and something else.
Ok, so, whats the first thing you would change?