Another amazing resource from Eat Seasonably are step-by-step tutorials for growing certain fruits and vegetables.
Also check out another great UK resource, the Royal Horticulture Society page. This will take you to a resource where you can select your fruit or veg of choice and find out everything you need to know for growing and harvesting it.
If you can't grow your own be sure to check out who is growing and selling in your area and support them by purchasing their local and seasonal foods. You can do that by visiting Local Harvest to find farmers markets or local farmers in your area.
This guide comes from the UK, called Eat Seasonably. The website offers great resources on what is in season. They offer a nice interactive calendar to find out when fruits and vegetables are at their seasonably best.
A video from a great website, dothegreenthing.com.