Good to see another digital artist here. If you really want to get into lighting you have to start doing photography and analyze why your picture looks the way it looks. Where does the light come from, how does it bounce, what other lights would improve that scene?

Most of the time having a hero object helps as well, you can focus your lights on just this object and you can play with it and determine why something looks good or bad. More importantly and probably the most difficult one is: what story do you want to tell with light?

I have been searching online for some lighting tutorials and found that there are not many out there. I think lighting is a very, very specific part of the "field".

Most of the time in environments like these a sun and a HDRI lighting scene do most of the work. If you don't have a point to focus on this might become hard to light, instead try to find a good composition to create with the landscape and trees.

In the end, your materials play a huge part in rendering and lighting. Make sure you have high quality materials and your good to start lighting. Another way to do it is by making everything a simple gray blinn material and start lighting. After you are done with lights, start shading every object one by one.

A good image consists of so many things. Good modeling, good materials, good composition, good lighting and of course efficient rendering.

If you really value "stills" that look realistic check out http://feuerroth.de/. This guy renders with V-Ray and renders about 24 hours on just one still to get the images he gets. Also he almost doesn't do any retouching.