When you're a small, independent filmmaker, there is so much that goes into budgeting and being able to put everything together. The most important thing you can do prior to going into production is to carefully plan.
There are so many different ways to accomplish this, but one of the easiest ways I've found is to use production management software (I use Studiobinder). For the version I use, it runs me $49/month and it does a great job of carrying me through from pre-production through post by allowing me to calendar everything out, build benchmarks/tasks and detail out my production with shot lists, storyboards & breakdowns - all the way through to call sheets.
I still use FinalDraft for my scriptwriting, but I can import from FD directly into Studiobinder.
There are other programs out there that might be cheaper and/or more flexible, based on your needs and budget. The point is: use something - even if it's just paper and pen.
Organizing your thoughts and planning out your shoots really is everything when you are bringing people together for a production - even if just for a few hours. It shows that you care about everyone's time, helps you foresee potential pitfalls, will help you problem-solve around those pitfalls, and will help keep your costs down.
Planning really IS everything when it comes to filmmaking.