In the previous blog post we discussed taking pictures of Moon with dslr. The reason for this post can be contributed to the fact that focusing on moon is still easier as compared to stars. Also, what to do when you are in middle of nowhere trying to take pictures of star trails, night sky, milky way, etc. It is hard to see your Camera controls on a night without moon and away from city lights.
Here are a few things I have personally tried when trying to do night photography. Pretty sure at least one of them would work for you.

1) Switch to live view and zoom in all the way using your camera functionality (not lens). Point it to the brightest star or moon, focus by rotating the focus ring manually. Lock the ring with gaffer tape or electrical tape.

TEST: Take a shot at higher shutter speed. If in focus, stars will appear as small shiny dots and clearly visible. If the focus is missing, they won't show up or would be blurry.

2) Use magic lantern. This software adds multiple inbuild functionalities to your camera. Here is link to magic lantern website where you can download the zip file for your dslr camera make and model.

3) Prefocus (auto) at a very distant object during daytime (mountain peak or a building) and then turn into manual focus.You have to be really careful about not disturbing the focus ring which might lead to blurred images.

Pro tip: To see your camera controls in dark, buy a red colored light source. It keeps the light disturbance to a minimum level and your eyes will adjust easily.

Be a dslr ninja.