The easiest way to make a homemade BBQ sauce is to trust what you like. Start with a base and then add what works for you. Use quantities according to what you are going to need, but I recommend starting with small quantities until you find the blend that you like best. The following are just examples to start you off.
Sour or Tart Sauce: Use a combination of lemon juice, lime juice, tamarind, plain and flavored vinegars. (Exp: white wine vinegar, balsamic vinegar, red wine vinegar.)
Spicy: Combine coarsely ground pepper, paprika, chili powder, cayenne pepper, garlic powder, cumin, fennel seeds, onion powder, ground ginger, white pepper, coriander seeds, ground cinnamon, ground clove, ground allspice, grated nutmeg, dried basil, dried oregano – mix with tomato ketchup – add a little brown sugar if it is too spicy.
Easy: Tomato ketchup, about 1 tablespoon brown sugar, Worcester sauce (just a splash), Tabasco to taste.