I believe in the survival of the plants best fitted to the prevailing conditions I'm lazy. So I chucked some relatively established plants in places - some things lived and thrived, some things died - added some small garden centre herbs where I knew I wanted to eat them soon - and tossed seeds around to fill in the gaps once the soil warmed up.
The Rosemary was (against all advice) a supermarket herb shoved into the 90% builders' sand, 5% leftover gravel from where they pebbledashed a wall with rude words painted on it and a scattering of compost left from doing my windowboxes (which are also a great idea for spring flowering bulbs/stuff that isn't edible). One of the lavenders was a roughly foot high plant - the English kind, not the more temperamental butterfly type - from the garden centre and, after it had finished flowering the first year, I chopped off the flowering bits and took strips of twigs with fresh leafy growth on them and poked them straight into the sand. Two years and they were happy, strong plants.
The tree was my treat. About three foot high and in a pot when I bought it, then put into a much bigger pot the following winter. Not cheap, but worth it for me. and maybe one summer I'll get more than three cherries before the pigeons get them
Everytime I get herbs from the supermarket or market (because I sometimes want something different), I'll get the growing type and, rather than throw it away or let it die, I'll take a chance and shove it in. If I've got seeds left over from sowing with A Plan, I'll tosh them wherever looks a bit bare. If something appears that I can identify/think it looks nice, I'll leave it.
The other thing I did was plant a honeysuckle by the door/window. The scent is unbelievable on summer nights. All I do with that is chop off the straggly bits at the end of the summer or now (if I've not got round to it and it's starting to sprout) and randomly hack off bits that try to come into the house.
If I were making a proper effort to grow food, I'd put a lot of things into pots or high up, as pests can be a right pain, but I'm not hugely fussed and won't use any pesticides. The price of that is losing things to slugs, birds or occasionally caterpillars (the Nasturtiums are a great sacrificial crop - cabbage whites love them - and you can eat the flowers and fresh seeds - I just scattered and left them to it, pulling up anything that went a bit too crazy). And I'd grow more from seed and more expensive, larger plants. But I'm not and I'm skint, more to the point.
I love the scents, the herbs that have survived, the bees (Bumbles, Leafcutters, Masons, Honeybees) and the birds that scoot around making the most of it and pissing off TwatCat because I won't let him out there if there are birds in the garden.
It's not a competition, just chuck it in and see what happens.
Except mint. Never ever ever ever ever allow that stuff to touch the ground. Or your whole garden will smell like a lamb chop hidden in a minty forest.