Important Things to Remember

Stain absorbs and dries much more quickly than paint.
Stain pigments settle more quickly than paint. Make sure stain is well-mixed prior to starting. Stop and mix the stain regularly while applying.
Apply stain in the direction of the wood grain.
Lap marks don't show up until the stain dries. Avoid them by brushing back from dry to wet. Work in small areas and do not stop in the middle of a wall.
Apply stain when the weather is agreeable. The best temperature is about 70° F. 50-90° F is the optimum working range. Wait for a day with low humidity and avoid staining in the direct sun.
Stain lapped siding from left to right, top to bottom. Stain vertical siding top to bottom. Either way, finish a section completely before moving on.
Work above the ladder to avoid marring the newly applied finish.
If you have some stain left over, do not use it to touch up the deck. Some stains formulated for siding are not suitable for flooring. Make sure you get a stain made for decks. The label should tell you if the product is suitable for vertical or horizontal surfaces.
Two coats may be required if the new stain is darker than the old.
Stain dries in 24-48 hours depending on house conditions and weather