Hello and Welcome!!
Looks like you are off to a good start! You may want to grade the substrate some, so it is lower in the front and higher in the rear, this will create a better since of depth in the aquarium, since you don't have a lot of space to work with you need to make it look bigger.
There are a bunch of low light plants you could get and try out, what I did when I was starting out here on TPT, I found one of the members with a huge sales thread with lots of scientific names of plants and started google searching away, then I came up with a list of things I liked and looked around for those.
As a low light tank you are not going to need much fertilizer, if you wanted to invest into some dry fertilizers they would last you a very long time. I have seen people have good results with store bought fertilizers like Seachem in low-tech setups, but in the long run, money wise, you are better off buying your dry fertilizers and making the solution yourself, Zorfox has an awesome post on how to make DIY solutions of different strengths. You could even try out some root tabs, the best ones in the hobby seem to be Oscomote+ root tab, you can get there here on TPT, best price I have seen is around $6 for 100. Plants will always get great benefits from co2, or a carbon source, and can be a great addition to your fertilizers. If you don't want to invest in a injected co2 system, you could try DIY or you could dose Excel. There is another chemical, can't remember its name, that is basically excel just a little strong and its supposed to be way cheaper, this may be an option for you if you are not wanting to go with injected co2 but don't mine $20 on an alternative carbon source.