An important part of building anything is learning how to iterate. As you get started with whatever you are doing you will make mistakes. This is not something to feel bad about it is just part of the process. As you start down a new path you need to focus on getting better and building a system of iteration. Each path that leads to a dead end also leads to knowledge and an opportunity to consider your process.
What you are looking for as you learn are sets of tasks within your larger project that are part of some smaller deliverable. For example with board game design my process thus far has been, to design a mechanic or set of mechanics. Do the needed updates to my spreadsheets of cards and rulebook. Make any needed card design updates along with other game assets. Then finally transfer into table top simulator or printed for playtesting. Having a set process like this allows the work to be more batched and to go more smoothly.
Now you need to remember that this is an evolving practice. Of course don’t take anything away that is working for you but do not be afraid of making changes if something isn’t working quite how you want it to. Going back to my example the next step for me will be designing a process for more regular playtesting (I have mainly just been solo testing thus far). This is going to end up being an absolutely pivotal part of making my game as good as I know it can be. I have no idea what the process for getting regular playtests with a wide array of participants is going to end up looking like and that is okay.
To build anything well it takes time and effort this is way it is so key to learn how to iterate cause building processes is really hard. The more you can set yourself up to have processes that you use to iterate the more you can expect to see success. I have been through those initial steps in my process now that I feel no anxiety about diving into the work which allows me to move quickly while making changes. I definitely still feel some nervousness while starting to work towards this next step but I know once I get the basics down and start getting into a rhythm it will just be another step in the process of iteration.