Like all Cucurbits, water carefully and sparingly at first. The small seedlings have a tendency to rot at the stem where it meets with the soil, particularly if over watered and the stem and surrounding soil becomes too wet. A good tip if this happens, or the weather wet, or just as a precaution, it's worth clearing the soil away from the stem to avoid it resting against the plant until the plant is more mature.
Once Cucumbers get established and start to grow it's the reverse, they require more water. If growing outside an economical use of space is to grow the cucumber up a wigwam/trellis which has the bonus of keeping fruit off the ground and out of slug reach. (for tips on keeping slugs at bay) As they grow cucumbers, plants need support up a wigwam, or to be tied into a cane.
Cucumbers are vigorous and produce a lot of fruit. Just like courgettes, a few plants cucumber plants go a long way. To harvest cucumbers, simply pick when they look ready to eat.
Like Courgettes, cucumbers can suffer from powdery mildew and if so, pick off worst affected leaves, water and feed. For an effective recipe to make your own organic spray, which will keep powdery mildew at bay, follow this link.
Whether in the veg plot or under glass, all cucumbers like plenty of water and do not allow them to dry out. Cucumbers can't be left unattended and you will need a friendly neighbour to water if you go away.
A tip when growing cucumbers is later in the season when there are plenty of flowers and baby cucumbers, stop the growth. Pinch out the growing tip so the plant's energy goes to the fruit development, not more growth. Don't let the plant grow too large at the expense of the fruit. Harvesting regularly which will encourage more fruit.