This is all about the practical details of getting a startup off the ground. It's a personal view based on experience, many things are easy when you've done them a few times but can catch you out first time.

Practice having good ideas:

• Having one good idea is rarely enough, things will change, you'll need to keep having good ideas
• Work out how you think best (for me it's long distance running with an A7 note pad and pencil)
• Read Thinking, Fast and Slow e.g. to understand your inherent bias towards your idea
• Keep a scrapbook/wiki of all ideas, it's good to go back and see what didn't go anywhere

Pick the best idea:

• What is the company going to do?
• Who are the competitors?
• Why is it unique?
• How is it going to be successful?
• Draft a quick business plan so that you have a story to tell others
• Buy a dedicated bound notebook and write all thoughts and meetings down
• Remember: If your idea seems to good to be true then it probably is

Good, that's the easy bit done!

Now do what is cheap and easy without spending much money (less than £1,000). The aim of this stage is to flesh out the idea without you becoming emotionally attached to it, you should be able to decide that it's not going to work and walk away:

• Read The Lean Startup
• Establish relations to stress test your idea:
  • Go to networking groups - don't be afraid of talking
  • Can you explain it to friends and family?
  • Make sure you get honest not sympathetic answers
• Pull together cofounders, especially if this is your first time
  • Research and discuss the equity split, e.g. The Very First Mistake Most Startup Founders Make
• Find friendly potential customers and get to know them and what their pains are
• Get your IP story straight (think what is patentable and what might infringe on others)
• Find a good name - hopefully you will be stuck with it for a long time
  • Register domains, twitter, facebook, reddit, etc
  • Register with companies house
  • Register with HMRC and file null returns every year
• Get a free business bank account but don't trade (that would get you into CT600's)
• Pick a good enough logo, think of a tag line
  • Get a few business cards
  • Put up a basic web site
  • Print a few T-shirts - they'll get people talking
• Make a record of all expenses in a simple spreadsheet and keep all receipts
• Pace yourself - this is a marathon not a sprint, it will take longer than you think and overcommitting can destroy everything

Now find some quiet time to ask yourself: Is it really a good idea?

If you are really sure you can take the pain, then go for it:

• Register for VAT as you'll not make a profit so best to pay no VAT
• Register for PAYE
• Find a good accountant (I can recommend Savvy)
  • Switch to their expenses tracking spreadsheet/package
  • Claim back initial expenses
• Decide on your risk profile:
  • Is it better to spend fast and hope to be first or take less risk?
  • How much time you want to spend on raising money?
  • How much you care about giving your investors a decent return?
• Learn the basics of seed funding (not forgetting SEIS/EIS):
  • Look at Seedrs, SyndicateRoom, Envestors, Crowdcube and the like
    • Get to know the site
    • Get to know what makes a strong pitch
    • Get to know common themes (apps, chips, bikes, etc)
    • Invest small amounts (over years if you have the time)
  • Look at grants (e.g. SMART grants from Innovate UK)
• Write a short, easily digestible business plan (if your idea is good it will be rapidly out of date)
• Start on IP protection (patents, trademarks)

Congratulations, you now have a Startup!

Things to remember/read:

• It will be a rollercoaster, scary and exhilarating. “If everything seems under control, you're not going fast enough.”
• Managing people is a huge overhead. You may think you are starting a tech company, you're not, it'll all be people management. The larger you are the harder it is to innovate, so get the foundations right before you scale the people.
• Reid Hoffman’s 10 rules of entrepreneurship
• Don't do things properly
• Ideas are just a multiplier of execution
• The Lean Startup again!
• Keep everything simple By the time you setup Airflow + Docker + Jenkins to your liking, the dude using cron + shell scripts is on his third failed startup.
• Do the right thing, act responsibly and with integrity. Your reputation is more important than your current startup.