"I did not have a concrete statement of work" As others have already pointed out, this was the biggest issue. You can "wing" a few smaller projects but when it

"I did not have a concrete statement of work" As others have already pointed out, this was the biggest issue. You can "wing" a few smaller projects but when it comes to high dollar stuff, you need more concrete SOWs. In software development world, concrete anything is hard. But you have to still try and ensure scope and client expectations are clear. I know that you have learned your lesson already. But just to reiterate, a good consulting gig is 90% about setting the right scope and expectations and only 10% actual delivery (my opinion). So spend more time upfront setting the expectations before you do any actual work. One approach is to make it milestone based. You deliver milestone x, you get paid $y. To test your clients on how they think, keep the first milestone short that can be delivered quickly. That will give you an idea of what is success for them.