Something to bear in mind here is actually not to cram too much into a container.

I am in my 7th year of gardening in containers (I have a very small amount of ground space, too) and I would encourage you to experiment, on occasion, with fewer of certain crops rather than more. I am gradually reducing the number of plants in my pots (except for potatoes, interestingly, where I am increasing them!!) and my yield has increased.

There are some particular things to consider here:

there is no doubt that seeds and plants get off to a good start in containers - often away from pests and in a good growing media - but you need to consider their long term prospects. It is not the same as close spacing in the ground.

Take carrots in a container.
Sow them thinly. In fact, I now place the seeds individually, or in a tiny pinch, evenly on the surface of the compost. If you are growing in containers, you aren't unlikely to be doing masses, so it is not a chore. It is true that just sprinkling them on will give you lots of carrots, but you will have to thin and my recent experience suggests that they bulk up more slowly. The thinnings, in my experience are pleasant but only a mouthful, so I try and leave well alone now.

Beetroot.
In the ground, small block-sown beetroot push apart well and roots that are left bulk up ok. In pots, the first ones appear to take the nutrients and when they are pulled, the remainder don't reach the same size. I recently tried planting single plug-grown beetroot in a pot, spacing them widely. I got a bigger crop overall because the root swelled quickly and evenly.

So, for beetroot and carrot I am now growing fewer in a pot, but they are a better size and I am having more crops in a year. Successional sowing is the way to go.

I am also producing better cauliflower, calabrese and lettuce now - larger, quicker growing plants with a heavier yield.

Be generous with your container space if you can.