In reply to craig h:
Still have some parsnips and savoy cabbage from last year. Planted my garlic in November, just sprouting now. Onions and leek seeds were planted two weeks ago (in a propagator indoors) and have germinated nicely, peppers (chilli and bell) and tomatoes will follow as soon as the onions and leeks are big enough to move to the greenhouse. Early peas will go in soon too. I also have seed potatos chitting. Later in the year, there'll be garden peas, sugar snap peas, french beans, carrots, parsnips, brocolli, cauliflower, savoy cabbage, sprouts, courgette, spinach, chard, lettuce, beetroot. I don't grow much fruit - only stawberries - because my partner doesn't eat it and I'd rather use the space for things we both eat.
Some tips that's I find helpful:
Around now is a good time for soil improvement. I use composted horse manure and put a layer a couple of inches thick on about 3/4 of my plot. The remaining bit is where I plant carrots and parsnips, where the root grows better if the soil isn't too fertile. Don't dig it in - the worms will mix it in eventually anyway, but for now while it sits on the surface it will be a good weed suppressant. I've done this for a couple of years now (cycling the area that I don't treat) and my crops have notably improved. It also helps with water retention, which is great in hot summers like last year.
For succession sewing, I find that using seeds from different varieties works best. If I plant seeds from the same variety, the second batch often catches up with the first batch to harvest at the same time, but the crop from the second batch is smaller. Planting a different variety for the second batch increases the chance that they will crop at different times.
For carrots, I dig a trench and fill it with sharp sand, then plant the seeds in that. Lovely straight carrots, and usually quite long as they send the root down questing for nutrients. Carrots don't like being transplanted, however if you want an early crop you can plant them indoors or in a greenhouse in toilet rolls, then when they are ready to go out, just plant the whole toilet roll in the ground.
I'm in Scotland where the growing season is quite short, so I invested in a greenhouse, which I insulate and heat. That allows me to get things started early so they have the best chance in the short time available.
I agree with the compostable pots - I want to like them but I've not had much luck with those either.