Talk to people that do stuff and they will often tell you about problems they have. if it is something you think you could do something about. talk to more people who do the same thing and see if they have the same problem. Is the solution already out there? could you do it significantly better?
They may also have an idea about a solution to give you a starting point. Is it a big enough problem? would it be worth your time building a rough MVP?
Show them the money. Show people where the money is in the idea. Show them you are a winner, you know how to plan and follow through on your goals. You are productive and can close deals. You know how to launch. When you do learn to write your own code, you will still need to be these things and more.
If you need $ now, exploit your existing skills and abilities that others will pay you for.
Hey, I too am an experienced python web developer with some iOS experience visiting SF this week and some of next. Does anyone want to show me his/her startup? My email is johnwlockwood at gmail.
try leaflet, and if you have a limited amount of data points you may just want to load them with one chunk of json/geojson and forget geospatial querying
Learn about a domain. Talk to lots of people in the domain. Ask about pain points, then imagine solutions.
Do you have a friend that is an expert in any industry? Often domain experts will have ideas about things that would help their industry.
I've been using Big Data techniques(using nosql and processes such as map-reduce) to do data analysis and to produce useful and actionable information. My data isn't super huge right now, my mongodb data directory is at about 33GB. It is a good start and useful for working out techniques that can be applied to much larger datasets.
Would they end up being a competitor to your site? if so why would you deal with them. or do they want it for some kind of internal tool?
You could sell them a license to run a custom version on their own system.
Are they looking for you to make all the changes? then to support it? do they want the source?