Everything below header is really too much basic and simple. I don’t know how much is picture in the header commercial and interesting for Theme forest except you are planning to make a template for NASA .
Keep in mind a few things, one those kinds of templates are a dime a dozen on TF so yours would have to surpass the rest to get excepted. Try to do something unique and usually that eases the way to get excepted. If you are doing PSD templates than you have to look at some of the templates that are on sale on TF so you have an idea on pixel perfects quality. I think the psd category is the hardest to get approved on.