Motivation issues

Break big seemingly difficult task up into small bite sized chunks. It often seems big tasks are hard to oversee or complete.

Play other (indie) games for inspiration or let others play a prototype of your game. Feedback can often be a good motivator.

Lack of an artist. Try to search artist forums in the free jobs section.

Realize sometimes making a game is just hard. But doing nothing does not get the game finished. With the good also comes some bad. Try and take a break sometimes to get a fresh start on a task. Also keep up your family, friends and sport stuff.

If they can dot it so can I. Successful indies and big game companies also started out small.

Don't lose sight of your (short term) goals. If you do not know were you are going with your current task or game it is hard to keep motivated.

Remember why you started or like game development. Probably also lots of nostalgic gaming moments as a kid.

Read up on some articles, forums or blogs on gaming or game development.