BBQ rubs are great alternatives to marinades. We like them better because they're easier and faster, and the flavor is stronger (not that there aren't advantages to BBQ marinades, too...). A "rub" is just a mixture of seasonings and herbs that you rub onto meat before barbecuing.
One of the great things about using a dry rub is that it gives BBQ meat a delicious crust. And it doesn't burn, like some marinades will. Some recipes say that you should apply a rub a few hours before you're ready to start cooking, but we've found it mostly unnecessary (but give it a try if you like, you might find it makes a difference). Applying the rub a few minutes before you barbecue is just fine.
To apply a rub, you can literally rub the mixture onto the meat. You can also sprinkle it on, if you prefer. We like to lightly coat the meat first with olive oil and then sprinkle the rub on. Once a rub is mixed or gets exposed to ingredients with moisture (like oil or lemon juice or even crushed garlic), it will become pasty. That's okay - it's just a bit more messy. Just go ahead and rub it on anyways. Don't re-use any rub that's been 'contaminated', either by touching the meat or by touching your hands that have touched the meat!
Store rubs in a tightly sealed container or in jars in the refrigerator for up to 3 months (6 months if stored in the freezer). Put a label on the container to remind yourself of what's in the rub, and write the date too so you'll know when it should probably be tossed.
The most basic of all is your simple salt & pepper. It always sounds too "plain", but honestly, something as simple as a sprinkle of sea salt and freshly ground pepper over a lightly oiled beef tenderloin is absolutely delicious! For a bit more of a flavor-kick, we sometimes rub freshly crushed garlic over the tenderloin first before sprinkling on the salt & pepper.
We keep this on hand all the time, and have used it for beef, pork, chicken, and even salmon in a pinch. Combine: 1/2 cup white sugar, 1/2 cup brown sugar, 3 tbsp of sea salt, 2 tbsp garlic powder, 1 tbsp onion powder, and 1 tbsp fresh ground black pepper.
This is a good, basic all-purpose rub for salmon. Combine: 2 tbsp finely grated lemon zest, 2 tbsp garlic powder, 2 tsp lemon pepper, 1 tsp dried dill, 1/2 tsp sea salt (or to taste), and 1/4 tsp finely ground ginger.
We cook salmon a lot, so it's nice to have a recipe with a bit of a spicy kick. This rub recipe also has a slight sweetness too. Combine: 4 tbsp brown sugar, 2 tbsp chili powder, 2 tsp ground cumin, 1/4 tsp sea salt, and a ground red pepper to taste (we use about 1/2 tsp).
Combine: 2 tbsp white sugar, 2 tbsp brown sugar, 2 tbsp finely grated orange zest, 1/2 tsp sea salt (or to taste), and 1/2 tsp finely ground ginger.
Combine: 2.5 tbsp brown sugar, 1 tbsp garlic powder, 1 tbsp onion powder, 2 tsp dry mustard powder, 2 tsp paprika, 1.5 tsp of dried basil, 1 tsp sea salt, plus 1/2 tsp each of savory, thyme, and black pepper.
Combine: 4 tbsp garlic powder, 5 tbsp dried rosemary, 1 tbsp sea salt (or salt to taste, if you prefer more), and 2 tsp black pepper. Lightly oil your chicken and then apply the rub.
Good on chicken, fish, even fresh veggies. Use dried herbs (not fresh) for this rub. Combine: 3 tbsp poultry seasoning, 2 tbsp oregano, 2 tbsp thyme, 1 tbsp rosemary, and 2 tsp each of basil and parsley.
These basic BBQ rub recipes are a good place to start... but feel free to customize them any way you like - they're forgiving and versatile! Add and remove seasonings and herbs until you find a mixture you really love.