You can always make better buddy. Here's some basic things that you should keep in my mind to make a mission good and admirable:
1. Plan a good story with good logic
2. Add objects and actors in a gameplay according to the situation
3. Don't make checkpoints far away, for it makes mission a little boring.
4. A good story context is always great to make mission remarkable.
5. Cheers! You are a skilled designer now.

Hope you practice these and you'll become great at designing missions. :D

ok!