What were/are the largest hurdles you face when building an MVP?

Marketing is a bit of an issue for me as well, especially at the beginning of a project, but also deciding where to go next with your product when you have 10000 ideas and not enough time and money to do them all so you have to start with one

For me, the hardest part is always the marketing/zero to one customer hump. My solution was to make sure my target demographic wasn't too broad, and instead identify a very specific group who's problem I could solve and market to.