1. Clean all areas where caulk needs to be applied. Use a putty knife, stiff brush or large screwdriver to remove old caulk and paint. It’s important to make sure the area is completely dry before applying caulk to avoid sealing in moisture. 
   
   
2. Cut the tip of the caulk tube at a 45-degree angle and insert the tube into the caulking gun. If this is your first time using a caulk gun, you may want to practice dispensing the caulk on a paper towel first.  
   
   
3. Hold the caulking gun at a 45-degree angle to the dry, clean edge that needs to be sealed. Press down on the caulk gun trigger and use a pulling motion to slide the nozzle along the window seal. The caulk should be immediately forced into the crack as soon as it comes out of the tube if applied correctly.
   
   
4. Every couple of feet, push the caulk you've just applied into the crack with a damp finger, knife or other object. 
   
   
5. Use a damp rag to clean up any excess caulk right away as it is difficult to remove once dried. 
   
   
6. Typically, it takes 12-24 hours for the caulk to completely dry, depending on the air temperature and humidity. Read the instructions on the caulk package for more information. 
   
   

If you're not sure which windows or other areas need to be sealed with caulk, the DIY Network suggests holding a lit candle close to suspected gaps on a windy day. If the flame moves toward you, air is likely pushing through. You can concentrate your caulking efforts on those areas.