did you go already?
I suggest any substrate but gravel :) Plants simply don't do as well in gravel (as in they still grow well... just not AS well) Pool filter sand is a nice cheap options if you are looking to do sand. Some other planted tank specific substrates such as floramax, eco complete, flourite also work quite well. You also have the option to do a Natural Planted Tank (NPT). There is a nice sticky on that here... In a Naturally planted tank, you probably won't need to worry about a cycle.
If you are just starting off I recommend hardy lowlight fast growing stems, these include (but are not limited to) Water wisteria, water sprite, elodea (anacharis), Guppy grass etc. I think water wisteria and water sprite by them selves can make the tank look quite beautiful due the nice shape of the leaves. For a bit of variety You might also want to throw a cryptocoryne or an anubias in :)
You might also want to go for a nice piece of driftwood to help give a focal point to the tank design :)
Water Dechlorinator helps detoxify chlorine which is harmful to living organisms. What cycling product did you get?