Solo startup founder here (of a not so successful SaaS startup yet(!)). First of all make sure you have a lot of money to spend. I know you will probably be able to code it up yourself (just like I do), but you will have spendings in stuff like advertisements, graphics, email outreach programs, hosting and stuff. Depending on your niche, you will probably need a LOT of advertisement money.
First of all. Try to find your thing. What makes you super excited (next to coding)? DO A LOT OF RESEARCH on that. Seriously, I can't stress that enough. One of my mistakes. Make sure you find something that you can improve, where is an actual market (still a need for it) and what doesn't take 10 years to build by yourself.
Make sure you create something that is different and better than other products on the market. That makes it soo much easier to market.
Things you should learn right now:
- Get the basics of accountancy. I know that it is pretty boring stuff, but doing this right from the beginning will save a lot of work later on.
- Read about advertising; funnels, copywriting, value adding, facebook marketing, influencer marketing and so on. Just consume it all and don't be afraid to test things.
- Save up a lot of money. You will likely run out of money sooner than you think. Everything costs money.
- Start interviewing people that are in your target market. Find out what you can do to make their lives easier. Try to sell time and/or money (as in savings) with your startup.
Last but not least, just do it :). Good luck!