For the past 2 years I have found myself getting quite bored with creating programs/games. It just does not excite me as it did when I first joined BYOND. I open up Dream Maker and 5 hours later I have yet to do anything. Recently I have been following some of these rules which have so far kept me motivated.
Go a different route when creating something you have done before. Time after time what ends my projects is doing something I have completed in preceding projects. So try going a different route when making it, read up on different programming methods and maybe try it out. Modular programming is a good thing to look up.
Construct a game which will be a challenge when programming. I thought the faster and easier the game was to create the longer motivation I would have to work on it. I was wrong, in my opinion programming is very fun when you are doing something new and challenging. It feels great to finally get something operational that you have been working on for a day.
Take breaks, just working on your game for days straight will drain you and your motivation. Try working on your game for a couple of hours and then go on a nice break away from your developing environment. I tend to thinking of great ideas when there is nothing on my mind, this will motivate me to go home, write these ideas down, and then work on the game later on.
Balance the challenge, in any game there will be parts where it is quite easy to create that piece of code. As said before, challenges should motivate you, but if you do all of the challenges right at the beginning you will run out of them. So you should balance them, first create something basic and easy, once you are finish go ahead and doing something hard.
What to do with graphics? For me, it all depends on what the project is. If it requires interesting graphics such as aliens then I will work on the graphics before I start programming. But if I have to draw basic items such as a human and swords I will leave them till later on. Many times I have seen people discontinue games because they can not find a graphic artist. Your game does not have to be the next realistic game on BYOND. Try using some basic graphics, such as a square for a human and maybe a line for your sword. If you wait weeks just for a graphic artist while doing nothing productive to your game you will loses motivation.
Feel free to add your own rules; it will only help me and possibly other users out more.