Keep up to date on your knowledge and don't be afraid to branch out into new areas to test the water.
The pies may be small but us humans have many fingers.
Occasionally you get to stick a digit into a big one.
Doing what I do I often find I have a six month lead on a new idea before some "me too" guy spots that there is a couple of quid in it and then copies it.
It's happened with the bolt kits and even with CAD designs that I've slaved over for days/weeks to perfect. Numpties with laser scanners can quickly replicate a design once they see it works.
Many years of trying to educate people into the virtues of R9 fuel hose has resulted mostly in other firms jumping in to the scene selling the cheap stuff.
You just have to keep innovating. Give good customer service. Oh, and know your subject....if you can advise technically with authority then people will trust you and give you trade.
And don't sell crap....stick to the good stuff. Same with quality of workmanship.!
On accounting - know what is deductible as overheads - there's more leeway here than most people think.
Car Park tickets from town being one most forgotten. You were there to drop a cheque at the Bank or check the balance on the machine.!