I also grow in containers and grew my first veg last year
I am not an expert at all, but last year I managed to grow courgettes, chillies, beetroot, tomatoes, green beans, spring onions, small aubergines, salad leaves, lots of herbs including coriander which is really easy to grow.
even though it's April you can still start now with courgettes and beetroot, salad and herbs can be sown throughout the summer at 2 week intervals
I bought 3 large wooden troughs (recycled from the double glazing industry apparently) from the Bristol Wood Recycling project at £3 each (a complete bargain), if you are local to Bristol you could pop down and see if they have more troughs this year
http://www.bwrp.org.uk/
good luck :)