Patience
Plants, lighting, substrate etc etc are all your own choice. Personally I would not use a desk lamp but beyond that you can use anything you would have in a larger tank, just choose smaller stuff! For a high light tank you'll likely need to go for 4-5 wpg or above, sounds a lot but smaller tanks need more light than larger tanks if you are aiming for a high light/high growth tank.
I have 2.5g planted tank. It'll be a year old in November. It isn't amazing and needed an adjustment period, but it is working extremely well now and is relatively low maintenance. A detailed description is in my signature as a journal thread, but here are the nuts and bolts below. I'm not saying it is the way to go. Others here, IMO, have much better setups with very beautiful scapes, but I'm extremely lazy and just like to watch fish and grow some plants. It takes very little to please me. The tank was also pretty darn cheap, which is always a plus.
Tank: 2.5g (had a glass hood once, but a rambuctious kitten ended that, so now it's an open-top)
Filtration: 2 red sea nano filters HOB. I over-filter 'cause I' overstocked, you should be fine with just one.
Substrate: Plain, very small grain gravel, with rootabs inserted on occasion. 1-3mm.
Lighting: One 13W CF fixture. It is a desklamp, but the CF isn't a spiral, it's U-shaped, which IMO better distributes light. It is about 5.2WPG and this tank is a LOW light aquarium. George used nearly double that WPG for his tiny nano.
CO2: I tried to make this high-tech once, but it was a pain in the rear and required too much time (plants grew to fast), so no CO2, not even excel
Ferts: None but rootabs, which I always forget to add.
Plants: anubias, moss on wood. A small grove of purposefully stunted Bacopa caroliana. This stemplant has yet to disappoint me. Great stuff. I've also grown crypts, rotala, alternantera, marsilea, and e. tenellus in this tank well, but the above combination has proven to be the most stable (slowest growing) and the cories like it best.
Fish: four corydoras aeneus that I've had for over a year. They were from a large chain store and were first in my tannic 20g, where they were getting by, but not really thriving. I think I have 4 males, as they are not very large at all. I moved them on a whim to this tank and they are much better. I think the very strong current from the two filters and the lack of competition has helped them. I know, overstocked, but this arrangement has really been an improvement for them. It started out as a temporary solution, but I think it may become permanent. I originally had 5, but one, which was already poorly in the 20g, succumbed in this tank soon after the move.
Heating: Really not essential. The tank will be at room temperature, which in my case depends on the season. In Summer, with my AC, it is at around 74-75 degrees F. In the Winter, we have no heat, but I live in South FL, so the temp can dip to the mid-upper sixties depending on where the tank is in the room at night. Again, great for Corydoras. Average room temperature is fine for most fish.
The stocking is up to you and what you're willing to do to keep the tank clean. I have to work at it a little because I'm overstocked. C. aeneus isn't the best choice, as there are a lot of pygmy catfish that are better suited to this environment, but these catfish aren't available in my area and my C. aeneus needed the move. I am lucky that the move was a success.
Good luck to you, a tank this small can be a challenge, but it can also be a lot of fun. If things go well at work, I'm considering moving this tank there, as it is quite peaceful and watching the cories dance is very relaxing.
llj
