Hi I'm thinking of chilles at the moment and some other herbs to use in my cooking but I'm a total novice
Chillies do well in a greenhouse with not too many problems. For herbs, I have had some fairly good results from buying one of those packets of growing herbs, splitting them up, and giving them room to grow.
A tomato or two can be good if you want flavour, much better than anything you will get in a shop, and I am germinating my first lot of basil now, but tomato and basil will be on the window sill for a bit before they go out to the greenhouse.
At the moment I am preparing beds, digging over, deciding what will go where and amending the soil with some compost and well rotted manure, if you jump on weeds this time of year before they flower you can stay on top all season, and feeding the soil will feed your plants.