Contrary to what you're asking for, I'm going to encourage you to let yourself be unmotivated for a bit.
If you're anything like me, I work really well in spurts and I build some amazing things when I'm in my zone. Sometimes I'm in that zone when I wake up one morning and I'll literally work all night long, only sleeping when I feel I need it for focus or have reached what I've aimed to complete.
And I might stay in that zone for a few days or a few weeks and then suddenly I lose motivation and what I've realized is that's often been beneficial for me. Because if I force myself to work, I produce crap, but if I let myself just be lazy, unmotivated, catch up on sleep and catch up with friends, eventually one morning I'm going to wake up again and feel really inspired to take up where I left off.
Sometimes that results in projects being at various phases of partial completion; however, I also have several projects that are fully finished and looking at those I know that I worked on them when I was really feeling my best and you can tell that.
For client projects, it's always that other 50% of the down payment that keeps me moving.
