Take 2 Cubes and 1 Medium Sheep...
Wait... WHAT!?
Well watch the video and you'll know.
Anyways, what I really wanna talk about is how I push my hard surface skills up, and perhaps it will help you out on your path.
Simply put - the variety of smaller projects.
Large projects can be fun as hell, and the can teach you a lot, but if you are starting your journey in 3D and don't have much experience yet, you may get stuck and then frustrated.
Shorter project and smaller ideas do two things:
1. Do not tire you much
2. They require you to think of a new design every time you start one.
So it keeps you fresh but also makes your brain go high revs.
When I record videos for YT for you guys, I always try to come up with a new fresh idea, or I try to put a spin on something that I have already modeled.
This won't tire you much, and will help you with creating new shapes from scratch.
And this is the thing that most artist struggle with - an artistic block.
So gather some references, look at them for a good 10, 30 minutes or longer.
Try to find something you like, grab one idea from the reference and make it your own.
That is how you can train your artistic muscles.
It takes time and patience, so keep going.
Remember - you will have failed only if you give up.
Best of luck!
ryuu