My (haphazard and minimally informed, but fairly effective so far I think) technique has been:

• Buy some seed balls. I got https://seedball.co.uk/product/bee-mix-bag/ and https://seedball.co.uk/product/annuals-mix-bag/ and scattered them liberally around the garden during the house-warming party. Not sure if any of these actually came up, but probably a few did! (Or I just got very lucky with some random things appearing)
• Use the app from https://www.inaturalist.org/ to identify what comes up. If not local and/or not good for pollinators, onto the compost heap it goes.
• Pull up half of anything that is threatening to take over (for me it was Green Alkanet, which has many things going for it, such as being an early pollinator, but was just totally taking over)
• Throw around some more wildflower seed that a friend gave me
• Think about buying some Yellow Rattle, to really kill off the lawn - https://www.wildgardenseeds.co.uk/WF%20Plant%20Notes/Yellow%20Rattle%20Fresh.htm
• Enjoy watching the garden grow, recognising that I am only its gentle assistant rather than trying to have any major power over it.

I've also planted some rhubarb, raspberries, rosemary, strawberries, and a few other bits, because I figure there's space for some tasty things for humans too.