Like all Cucurbits, water very 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 or the stem and surrounding soil becomes too wet. A good tip if this does happen, or the weather very wet, or just as a precaution, it's worth clearing the soil away from the stem to avoid it resting against the plant until there is strong growth.
Once Cucumbers put on growth the reverse is needed, more water is required to keep the cucumber growing. If growing outside an economical use of space is to grow the cucumber up a wigwam/trellis which has added 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 wig wam, or 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. Whether in the plot or under glass, all cucumbers like plenty of water and do not allow them to dry out. It follows that 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 to make sure as soon as the flowers form with plenty of baby cucumbers, pinch out the tip of the plant 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.