Definitely introducing some sane planning and prioritization helps. A lot of startups fail because they end up reacting to events around them and are constantly fire fighting. That usually means a lot of work gets done, people are very stressed, the goal posts keep on moving, and things don't actually progress a lot and are possibly getting worse.
Ultimately, the amount of work you do does not matter if it doesn't get you closer to where you need to be. So, the most valuable thing you can do in a startup is figuring out the big picture. You can't fix all the issues. You are starved for resources and time. So you need to be super picky about which things you actually do and when. In fact, mostly this is about deciding which things you definitely aren't going to waste brain cycles on. Perfect is the enemy of good here. It's a given that you are going to have to take short cuts on some topics.
In practical terms:
- Identify what is really blocking the business. Start removing those obstacles. This requires that you understand both the business and the tech. That's the classical role for a CTO. A good CTO needs to be all over product management, business development, and sales so he/she understands what is being sold and how the product aligns with that. The tech is a means to an end and needs to serve business goals. Why are sales deals falling through? What's missing in the product that makes it not fit the market? Etc. Ask those questions and figure it out. Understand why this is not working out.
- Then write down the ideal end state of your company some years down the line. Basically, define the strategic goals and translate that into short term tactics to get to those goals. Shoot for something that is actually doable and realistic. At least on paper.
- Break it down into things you do not yet have in the product that would work towards that vision. Think in terms of themes that you can strive to improve rather than a long feature list. This isn't a backlog. It's gaps in your product where your lack of progress is holding back the business in some way.
- Prioritize these themes by quarter and year and argue why these are the most important things to tackle next. Basically, you plan a few quarters ahead and you front load the most critical things. This is your roadmap. Realistically, cap the number of themes per quarter to just a handful. "I want it all, I want it now!" is not a plan but a great line from a song by Queen.
- Organize your backlog of features, nice to haves, tech debt, enhancements, etc. by value and difficulty and align with your roadmap themes. Only do those things that are aligned, valuable, and doable and in order of priority. You will never get to the bottom of that backlog. But if keep chipping away at the most valuable things first, you should be making the company better over time. This is what a good product manager should do together with the CTO. In some companies this is one person: a technical product manager.
- Revisit the plan regularly and divide work you are doing day to day into "unplanned things that just have to happen" and "things that make progress on our roadmap". About a 30/70 split of time is ballpark a realistic goal. There's always shit to deal with but you want to keep on making progress on your real goals most of the time. Anything else, you don't waste time and energy on. The benchmark of success is clear visible progress on the themes that were identified as the most critical. If you have extra time, start working on the next most important thing. No reason to sit on your hands.
Get consensus from anybody that matters in the company that this is what the company does. You'd be surprised how many startups don't even have that consensus and are just operating day to day on the whims of some erratic C-level types with short attention spans. Basically, insist on some realism. You're not looking for wishful thinking here but something that is doable and valuable. Beware of CEOs that suffer from magical thinking here that just gloss over all the obvious issues that will ensure the goals are perpetually unachievable. I've seen this in action a few times where they just assume a knight in shiny armour will come along and wave their machine learning sword around a bit and will turn them into the next Steve Jobs. Never happens without a real plan.
Stop reacting, start planning and strategizing. Figure out the hard issues. This is how I've been running my current startup. It's hard. There are so many things to react to and almost all of them are horrible time sinks.