I know what you mean, my tanks are not high tech, although I did invest in pretty good lights. With the 37g you could just get miracle grow plant soil and cap it with a layer of sand then gravel like you have. To save some money. Make sure your gravel is twice as thick as your soil, and fill by putting water on a plate to not disturb the substrate. Fill and drain a few times, so you don't have fertilizers from the substrate going around in the water column, and you should have a pretty nice setup, if you have good lights. The seachem excel, I use that to keep algae down, and my crypt plants seem to like it.
The picture in my avatar is a tank similar to that one you posted. (90 gallon.) Only difference is I have malaysian driftwood. (it sinks right away.) which can be picked up at most local fish stores. The plants are java fern, a common cheap easy to grow plant. You tie the ferns to the driftwood with sewing thread, and they naturally attach. I have a coralife power compact light that I run for 6 hours.(If I did it over, I would of ordered a T5 HO light from dr fosters, new they are under $200, but the compacts came with my tank (used.) All plants are attached to driftwood for easy cleaning, due to large fish and bio load. Stock is bichirs, one orange severum, and an african leaf fish. gravel looks very similar to yours, I got 2 bags at walmart for it..the most natural looking they had. I don't like plastic decor, I always find nice pieces of wood, it is easy for me though because I live on Lake Erie, and find some sweet pieces after the storms. I still do like malaysian if I can find a cool piece that is like a cave/stump or something. As for wood, I collect pieces already water logged or somewhat wet (so I know they will sink) some driftwood seems to take forever to sink if it was dried when you collected it, boil them, twice. and scrub them after each and soak for a few days with a couple caps of bleach in a 5 gallon bucket before I put them in.. then resoak in clean water.
If you need any help along the way ask, I got alot of my ideas for aquascape from the photo lounge and other planted sites, and just went with what I liked most. Always liked the more natural looking tanks, with nice aquascape, more than the ones with the "rare" everybody wants fad fish of the month.