The plants will look good once they start to grow. I love the Val on the side of the tank. I am not really sure I am feeling the Hard scape. It looks like too many Big chunky things for a small tank. When you do a hardscape on a smaller tank it is best to use smaller rocks and thinner wood. That way the tank feels bigger.. Its like putting a pool table and huge L shape couch in a room small room. I like the plant placement. it will be interesting to watch how this tank changes.
My advice: Grow plants first, worry about hardscape later...
Now that your lighting is in order, keep the tank very clean. Remove dead leaves as you see them, and rinse your filter regularly. If you see that the tank needs another waterchange, do it. Don't wait until your scheduled waterchange. Sometimes new systems will need larger waterchanges every other day just to keep things clean. Already looking at your picture, you need to clean that filter, those clogged up plants gotta go. That stuff produces ammonia, and that's not good.
You asked in another thread about the fish load. I'll answer you here, because I've kept fish for about 22yrs. You should be fine with the levels of tetras and danios that you want, eventually. If you increase the numbers gradually, you should be fine. If the tank is densly planted, your stocking doesn't really follow inch per gallon, but is more of an eyeballing thing. I personally don't like Danios in anything smaller than a 20g. They are an active fish and swim very fast, so for me, long tanks are ideal for their habits. A 20 long is good, but a 40g breeder is amazing. Zebra danios are underused, IMO, a potentially amazing fish in the right planted setup. Would love to do a setup with vallis, sags, river rocks, and Zebra danios and then crank up the flow. Very elegant, I think. The cardinals will be ok if the water is kept clean, which you're supposed to do for the plants anyway. Happy plants = happy fish!
Liz