There are no RTS tutorials that I've seen. As others have said, an RTS is a gigantic topic that would be too much for a single tutorial, especially if you're a beginner.
I would gradually build it up from smaller pieces. First decide how you want to do animation. I would look into an instanced skinned model technique, since you'll likely have dozens of the same units at the same time. Then make a camera that you can zoom in and out (hint: look at Supreme Commander for the de-facto RTS zoom. Actually it does pretty much everything spot on, so you could probably learn a lot from it). Then figure out how to select units and give them move orders. Then add terrain. Add more units and a UI. etc etc etc.
I know that there are tutorials for many of the smaller pieces such as selecting units and making a camera, so the trick is to combine what you learn from them all in an organized, sustainable code structure.
"No programmer can pick up a TV remote without thinking what it would take to add a stun gun. [...] Their motto is 'if it ain't broke, it doesn't have enough features yet'" - Scott Adams,
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