If you've never sliced the top of your thumb cutting open the edge of a tube of caulk, you have greater dexterity than most part-time home handy workers. I grew up around ratchet-rod caulk guns and cursed a few. Today's drip-free caulking guns operate by a spring-loaded pressure rod that works smoothly from the pressure of your finger. A quick trip to the hardware or home improvement store can convince you that there's a wider selection of caulks and guns than you've seen before.
You need the right caulk for your project-at-hand. Shop wisely and ask a clerk for help. Generally speaking, you're probably looking for:
So you have the caulk in the gun and you're ready. Hold on, turbo! Even the best-quality caulk may have trouble adhering to a dirty surface or crease filled with remnants of old caulk. It won't adhere to soap, either, so clean the surface with plain, warm water. To root out old caulk, you need anything from a sharp blade (for silicone) to a heat gun, screwdriver, or caulk softener (for latex or acrylic).
Cut the tip of the caulk cartridge at the business end of the gun to match the depth of your job. Use steady pressure on the trigger as you work the tip at a 45-degree angle to the area you're filling. And here's a tip you might otherwise overlook: always caulk a bathtub when it's filled with water. Otherwise the tub rides high and when it's filled for the first time, the weight of water and bather can crack the new caulk.
It's best to work at a careful, steady pace to get the caulk applied during a single repair. It can try your patience to match up your tracks and at the same time lay down a seamless, protective sealant. Caulk, like other adhesives, cures as it sets.
If you're caulking cracks in your exterior concrete, be sure to buy siliconized latex concrete caulk. Again, your success depends on how well you clean the cracks of debris and old patching compounds or sealants.