The "PLAN" is to have enough money to do a very thorough preproduction; being able to pay all Dept. Heads/Keys and the lead and supporting actors, and at least expenses plus a token payment to everyone else; to rent excellent gear for as long as you need it (or as a part of the fee for the Dept. Heads/Keys - camera, lighting, production sound, etc); to not have to rush when on location (part of "thorough preproduction"); to have all necessary wardrobe, props, transportation, etc.; to take care of your cast and crew almost as if they were stars; to have a complete, thorough post done by professionals; to have plenty of funds for festivals and marketing. And to have a slush fund for emergencies.
This does not mean that it can't be done on the proverbial shoestring, but 99.9999% of indie filmmakers never think the project all the way through. You need to plan more thoroughly than a "Hollywood" production as you don't have the large budget to begin with and need to get the most out of what little budget you do have.
Patience, patience, patience, patience, patience, patience!!!!!!!!!!!! Preproduction, preproduction, preproduction, preproduction, preproduction, preproduction, preproduction!!!!!!!!!!!!!!
Then double down and be more patient and do more preproduction.
A line producer can be a huge help here, as can a production accountant.