--A quick note--
This is assuming you have your aircraft imported from a dnm, as opposed to a brand new scratch model that hasn't been exported yet. This is because of Material properties that will be discussed later.
The basics
It is extremely easy to set up a quick render. All you need are 2 more objects in your scene: a lamp and a camera. I will be using CEP's Su-24M for this part of the tutorial.
From the Add menu, add a camera and a Hemi lamp (for simplification purposes).

Why use a Hemi lamp? That is because it provides excellent all round lighting without major tweaking.
Now go into Camera view.

Positioning the camera while still in orthographic view can be quite a pain, as you aren't exactly sure what the camera is looking at. Fortunately, Blender cameras have a Fly viewmode that can be activated by pressing Shift-F while in Camera view. This way, you can control your camera in 3 dimensions while still allowing you to obtain the best shot of your work.

The 2 dotted borders represent the borders of your render. Once you are satisfied, hit F12!

That's it. Save your render by pressing F3.
Improving your first render
So you've got a shiny, sleek looking aircraft that really looks spectacular. But as you can see, the background isn't all that great, and neither is the resolution.
These are easy to fix, however. For the background, you can change the colour and the gradation of colour of the background, or you can make it transparent altogether.
In order to just change the colour, go down to the Shading button.

Click on World buttons.

Here you can select your base colours and ambiance.

1) Bottom colour. This is your primary base colour which is used as default background colour or as the background colour at the bottom of the render if you choose to have gradation of colour.
2) Top colour. This is your secondary base colour of which would be used as the background colour at the top of your render if you choose to have gradation of colour.
3) Ambiance. Essentially this changes the overall colour of your aircraft, similar to using a light source which emits different colours.
To allow gradation of colour, click on Blend. Real and Paper have a different kind of gradation that I don't consider aesthetically pleasing, but you can experiment with them.
To improve the resolution of your render or make the background transparent, go over to the Scene button.

Go to Format and change SizeX and SizeY to your liking. However, this changes the borders of the camera, so adjust it accordingly.
To make the background transparent, click RGBA at the bottom of the Format tab. This will not show up in the render window, but the background will be transparent when the image is saved. You can also change your render image type, which ranges from jpg to bmp and png.

Taking it to the next level
But the Hemi lamp isn't perfect. It disallows the formation of shadows, which play a subtle but crucial role in the render. Hence, we will be switching to the Sun lamp as the main lamp, relegating the Hemi lamp to a less major role.
Add a Sun lamp as per normal.

To allow the formation of shadows, select the lamp and go to the Shading button. Click on the Ray Shadow option and change the colour of the shadows if need be.

The position of the lamp does not matter so much in the creation of shadows, but its orientations do. Experiment with the different orientations to cast the shadows you want.
As for the Hemi lamp, it is to create light from the surroundings. In real life, light does not come entirely from the sun or a lamp, as some is reflected off other objects. So, to emulate this, flip the Hemi lamp 180 degress so that it is now facing up instead of down.
Again, go to the Shading tab. The Hemi lamp is bright on its own, so having 2 lamps gives an extremely bright render. So we are going to tone down the brightness of the Hemi lamp. Go to the Energy tab and give it a value of 0.2 or 0.3.

Render and voila!

Textures
This next section talks about renders which require the use of textures, mainly for aircraft on the ground. For this you will need to know about materials.
Materials
Materials are basically which elements of an object are used in the render. These material settings can be accessed and edited under the Shading button. When you import a dnm, the materials are automatically set for you.

VCol Light - Makes your object glow in the colour you have given it in Vertex Paint.
VCol Paint - Makes your object possess the colour you have given it in Vertex Paint, but does not act as a light source.
TexFace - Allows mapped textures to show up in the render.
These 3 options are basically all you need to know for most renders. A refers to alpha channels, which are generally redundant.
However, when you create a new object, it does not have an associated material. Hence, when you try to render that object, whatever colour you have given it before, it would not show; rather it would just be white.
Hence, when making scratch models, before making a render, give all your objects a Material and select Vcol Paint.
From here on, I will be using Decaff's 787.
After positioning the aircraft and setting up with all the settings that have been mentioned, create a new plane as the ground/runway.

Map an image onto it as the desired texture. For this I will have to use Decaff's tutorial from 5:20 onwards: There is no need for precision here

After mapping the texture, go to the Shading tab. Add a Material for the plane, and enable TexFace.

Voila!

That's pretty much all I know for now. I do know a bit of Blender videos, but it is extremely tedious and not quite worth the effort.
Have fun experimenting with your WIP shots! If you have any queries or anything to add on to this tutorial, feel free to post below!
-NR