Technique: No Flap Landings
When you extend the flaps on your plane, you lower your aircraft's stall speed, and at the same time, increase drag. This all happens because extending flaps increases the camber, or curvature, of your wing. When your wing has a higher camber, it also has a higher lift coefficient, meaning it can produce more lift at a given angle-of-attack. Extending flaps reduces your aircraft's stall speed for a fairly simple reason. Because your wing creates more lift with the flaps down, you don't need to as much angle-of-attack to balance the four forces of flight. And because you can fly at a lower angle-of-attack with flaps extended, your stall speed will be lower as well.
Without flaps, you'll lose all of these benefits. You'll have to fly a more shallow approach, at a faster speed, with more ground-roll.
Why Practicing No Flap Landings is Important
A variety of electrical and mechanical failures could require you to perform a no-flap or partial-flap landing. Most airplanes have specific procedures and speeds prescribed for this. You may also find a no-flap landing helpful in a few non-emergency situations. If you're flying a light airplane into an airport with a long runway, you don't have to worry as much about stopping distance. Choosing to fly a no-flap landing could help you in extremely windy conditions, especially when you need to maintain positive control of the aircraft in a maximum crosswind situation. And if you're flying into a busy airport, no-flap landings could allow you to fly a much faster final approach to landing, making ATCs job a lot easier for faster jets behind you. Approach and landing in icing conditions might necessitate a no-flap landing as well.
Adjusting Your Pattern
If you're flying a traffic pattern without flaps, you'll find yourself with a relatively nose-high attitude, as compared to flaps extended. Losing altitude will be more difficult without the benefit of increased drag, which means you'll typically need less power. To make things work, you might need to fly a slightly wider, traffic pattern.
Flare, Touchdown and Rollout
In light airplanes, no-flap landings aren't exceptionally difficult or dangerous. No-flap landings may require up to 50% more runway distance for stopping. With flaps retracted and power reduced, the airplane will be slightly less stable around the pitch and roll axes. While you should avoid the temptation to "force" the airplane onto the runway, you also shouldn't flare excessively, which might result in a tail strike. The best thing you can do is focus on a solid, firm landing without too much concern for greasing the wheels on. No-flap landings aren't usually the time for a soft-field technique. On rollout, you'll find yourself having to use more braking to slow down without the added drag of flaps.