1. Investigate writing fundamentals, golden rules from authors or tips/tricks
2. Elaborate a schedule where you can organize your concentration
3. Put away distractions
4. Try to write between 500 to 3000 words per day. Also, consider the importance of writing in the early mornings
5. Take notes or make documents where you will store in order important factors of your story such as: general plot, plots per chapter, lines of events, character sheets, settings, data, extras, etc.)
6. JUST FUCKING WRITE and be consistent. No matter if you see it as a dream job or a hobby. Just get it done.
7. Once you are done, you can take it anywhere you please, wether is publishing on the web or asking some publishing house to sell your work.
Even though, you may be doing science ficition, get inspired by consuming books, movies or videos related to that theme.