Plans are tricky things to get right.
There's a technique developed (as far as I can tell) by the Center for Applied Rationality. They call it Murphyjitsu, after Murphy's Law. If anything that can go wrong, will go wrong – then take the time to imagine all the ways your plan could fail in advance, and change the plan to make sure they don't happen.
They describe this process as taking only a few minutes, but I've found you need to stand up and walk around at the very least to make sure you find all the strange ways something could fail. And that's just for the reasonably high-probability ways.
I sort of want to share my own Murphyjitsus, to give you guidance on how to do your own – but that was before I noticed there was a Google Docs Template for the process.
I cannot overemphasize how important this can be. Most people have goals they approach in a somewhat random, or merely comfortable way, devoid of context or awareness of their smaller failures. That's probably needed, for mental health. But we should take time, every once in a while, to seriously and critically look at our own plans and actions to make sure we can recognize what could go wrong before it does. We shouldn't be paralyzed by it either – so many people are put off by the seeming impossibility of a thing, and that's harmful – and harmful in a way Murphyjitsu won't fix.
So my auxiliary recommendation is to first develop a plan for something you want – something so stone-cold stupid it couldn't possibly work. That's OK. Then imagine, what's the most effective thing I could add to this, to make it less laughably implausible? Repeat until it becomes at least logically possible for you to succeed.
Take the time, before you navigate away from this, to go through this two part process for something important. Start with a silly goal, make it something that could theoretically work, and then start attacking the ways it could fail, noticing all of them. When you have a plan as good as you can make, reflect on whether it is a cost worth paying to achieve your goal. And then email me. I'd like to talk to you about this type of thing.