'Cut and come again' mixtures

 Hello there

I am wondering if anyone could please give me some advice about
growing  'cut and come again' salad mixtures? I've not grown any
before and am not a very experienced gardener! :)

The two seed mixtures that I have contain the following:

Salad Rocket, Chervil, Corn Salad, Red Batavian and Sugar Loaf Chicory

and

Rocket, Sweet Basil, Oak lead Lettuce, Broccoli Raab and Italian Red
Dandelion


I have sown a couple of rows of these seeds which are now coming up
nicely. I know that they can be harvested when they are a few inches
high but do they need to be thinned out in order that each seedling
develops into an individual plant which can then be harvested a few
leaves at a time? Or should the seedlings just be left as they are,
growing in a dense-ish row and cut as required? Or a combination of
the above?

Any help would be gratefully received!

All the best

Ruth