Planting Depth and Spacing - A guide depth to planting your bulbs is to cover over the bulb with two to three times the depth of the bulb itself. So a tulip bulb which measures roughly 3" long would go into the soil so that its top tip was about 6" deep in the soil. This sounds a lot, but if you have that depth of reasonable soil things will be quite happy. A small crocus bulb only 1" long would go in 2-3" deep. Spacing betwen bulbs is largely dependant on the flower size - large flowers or large leaves need greater spacing. The bags of bulbs will come with spacing suggestions as well as with brief planting instructions and a suggestion to the depth of planting, particularly for the few exceptions, eg. Lilium candidum and Nerine bowdenii.
Preparation - Dig over the general area you are planting in beforehand to remove competitive weeds and allow the air content of the soil to rise, this will aid the entry of winter rain.
Feeding - Fertiliser in the form of bone meal or another form of slow release plant food, and leaf mould will help, but remember that this may well encourage weeds to grow more vigourously as well. Most bulbs only grow slowly through the winter and fertiliser is rarely limiting at this point. During rapid growth and flowering it becomes more critical as bulb mass is being exhausted and has to be replenished before the dormant period sets in again. Fast growing bulbs with bigger growth habits - the Crown Imperial Fritillaria for instance will benefit from liquid feeding whilst in growth as they have so much ground to make up before they again go dormant.
Labelling - Do label your planting so that when the bulbs flower you will know what they are, but equally when they go dormant you will remember not to dig them up as you garden over them.
Waterlogging - Most bulbs hate waterlogging for any lengthy period. They are plants that prefer free draining soils, try and avoid such areas unless the bulbs are suited to it - Camassia and some Leucojum would tolerate some waterlogging.
Irrigation - Spring flowering bulbs tend to need a dry summer rest. Once the leaves wither they are formng a protective skin and lying low waiting for the soils to cool again and rain to trigger another growth cycle. Irrigation of other plants around them may therefore not be beneficial.
Space - The Eremurus, or Foxtail lilies, hate being overshaddowed by other plants. They do need the sun to be able to get to the soil arond the plants, presumably to warm the soil.