Fall is THE time to plant bulbs like Daffodils, Tulips, Crocus, Hyacinth, and many other spring-bloomers.
Many people also ask about summer-blooming bulbs, such as Dahlias, Lilies, and Gladiolus. Those varieties become available in the spring for planting.
Bulbs get planted the season or so prior to their bloom-time. Or, another easy way is just to come to the nursery in the fall and the spring and we will have exactly what you need at the correct time =)
Most spring-flowering bulbs like at least 4-6 hours of sunlight. They also do very well under deciduous trees, since the trees will not have leaves until after the bulbs come up.
Bulbs can rot in over-watered, or poorly-draining soils, so make sure to mix in compost for nutrients and drainage before planting. Give the area a quick weeding while you do it, you'll thank yourself later!
Pointy side goes up. Easier said than done with some types of bulbs. If you can't tell which is the pointy side, look for the side with roots, and put that face down. Worse case, plant the bulb sideways and let geotropism (your word of the day) take care of the navigation.
Use the planting guide on the package as a guideline for how deeply to plant your bulbs. If no instructions are available, a good rule of thumb is to plant bulbs about two-to-three times as deep as they are tall. For example, a 2" daffodil bulb would be planted roughly 4-6" deep. Make sure to factor in the depth of any mulch you are using on top. Be careful not to plant too deeply, or the bulbs may not emerge or flower.
Set and Forget
Give the bulbs a good water to settle the soil around them, and then leave them alone. The fall and winter rains will take care of their water needs.
Fun with Containers
You can also layer bulbs in pots. Simply plant the largest first (daffodils and tulips), then work up to the smallest (crocus, dwarf iris, and hyacinth). The smaller the bulb, typically the earlier the flower, so you will get continual color as the season progresses.