HelpfulGardener.com

Valencia Orange, in ground for ~2 months, bought at around 3-4 foot high, looks healthy but no new growth at all. Amended the soil originally with some Miracle Grow for Citrus stuff, watering deeply, but only when it dries out, and gave it some citrus fertilizer last week.

The leaves are all dark green and shiny, but it's just not doing anything.

I'm concerned it's not getting enough sun. It's full sun, but the sun goes dappled off and on as it moves past this location.

What are the symptoms of not enough sun? Anything else I should be doing?

It might take a while for the tree to get accustomed to the new environment.
I wouldn't worry, since looking healthy.

I agree. A tree needs time to get used to its new environment. I got an apple tree 4 years ago. The tree did not grow for over 1 year. This is completely normal. Don't worry.
Only if you see that the tree is loosing it's leaves, looks weak, then post a couple pictures and we'll help.
But right now, as I said before, I'm sure it is okay