My biggest problem in creating a game is that i suck at design.
You can sit around complaining, or you can do something about it.
Bad design comes from a critical misunderstanding of what makes games
fun. Fun comes through learning, which means you need to develop a scalable challenge that can only be beaten with the mechanic you want to teach your player, and you need to give them a reason to care about getting to the finish.
Do some research on your favourite games, and break them down in dot points about what their Goal is, what Challenges you faced, what Mechanics you had to overcome the challenges, and also what types of Feedback were given to you to let you know you were doing well/bad.