First off, buy this book. One of several grilling books I'd consider essential for guys that like to grill:
For grilling party beer I always go Mexican, either Tecate, Pacifico, or Modelo Especial.
You want a good assortment of goods. Pick 3 proteins:
-Sausage
-Chicken
-Skirt Steak
-Burgers
-Hot Dogs
Those are the staples. Let's break each one down, but before we do, I'll address the SINGLE most IMPORTANT aspect of grilling: getting good color on the outside, withOUT burning it, while making sure the inside is cooked exactly where you want it. This sounds a lot easier than it is, and it requires years of practice to master. However, just be aware. Every protein has its trick, but the basic idea is to FLIP OFTEN. I know that's contrary to what many a grill master will tell you, but this is knowledge from working a woodfired grill at a 1-Michelin star restaurant in L.A. FLIP OFTEN. Make sure your grill is hot enough so it won't stick. If your grill is thoroughly clean, and there's a VERY light coating of oil on the food, and it's hot enough, your food will not stick. The other trick is knowing how to find the right heat. For this reason, I recommend starting with a gas grill first, and then transitioning to coal, and then transitioning to untreated wood, a true test of grill mastery. Always keep one side medium-hot and the other side medium. Get your color on the hotter side; really nice even browning, crisping up chicken skin, getting good dark color on sausages or meats, and then move them either on the UPPER rack if you have one, or simply move it over the medium side, to finish cooking the interior without burning the exterior. Do your absolute best to prevent flare ups: have an even cooler part of the grill where, if the food starts flaring up, you can put it on the safe zone until the fire dies down. In a worst case scenario you can just keep a plate next to the grill to move food to.
-Sausage: Always buy fresh sausages. The style is yours to pick, there's literally 500 different types of sausage out there. Try to find a local butcher or sausage maker to buy from. But high end grocery stores always have a nice one. I'm not a fan of chicken or turkey sausage, there's something pretty gay about that. When I think sausage, I think pork, even if there's nothing other than breakfast sausage. Don't buy pre-cooked. Cook these medium well. The SLIGHTEST hint of pink in the middle is totally safe, considering sausage is usually mixed with curing salt, and this will keep them juicy. I used to bbq a couple summers ago at an ex-gfs apartment complex poolside, when I was working at a restaurant that made homemade Lucanico sausage (Italian fennel sausage) that I would bring home. I'd grill it over hardwood; just watching people's reactions was pretty funny. Orgasmic. I've still got the recipe somewhere if anyone's interested, but you need a meat grinder and sausage stuffer. For serious meatheads.
-Chicken: Super easy if you don't fuck it up. You want a mix of dark and white meat. Ask your butcher for a whole chicken, cut into 8 pieces, bone on (cooking on the bone keeps it juicier and produces great flavor). Chicken marinades are super easy, I usually just throw something together that's a variation of citrus juice (lemon, lime, and orange) spices (cumin, coriander, black pepper, paprika) garlic, onion, and fresh herbs (cilantro, rosemary, oregano). Seriously, mix any of those together in a blender, put the chicken in a large freezer bag, and marinate the bird in the bag overnight. Make sure there's a couple spoonfulls of olive oil in the marinade. Cook the dark meat about 5-10 minutes longer than the white meat.
-Skirt steak: I like rubs. Similar to chicken, I'll mix together any variation of cumin, coriander, black pepper, and paprika. I add a LITTLE brown sugar, but you have to be careful because it burns. Cook skirt steak medium. If you've got nicer steaks, like NY or ribeye, cook them medium rare.
-Burgers. The first trick with burgers is the accompaniments, which is why if I'm doing burgers, I'll only do one other option. You want iceburg lettuce, sliced tomato, thick cut onions to grill, mayo, mustard, ketchup, good buns, cheddar or american cheese (I go for gruyere) and nice fat 8oz patties, at LEAST 20% fat. I go as high as I can find with the fat percentage. Don't bother with Kobe burgers, that shit is just marketing. DO fuck with burger mixes that have dry aged meat in them. The flavor is noticeably better, producing a little gamey flavor. I cook burgers medium unless some asshole wants it well done. I put the cheese on while the burger is medium rare so that by the time the cheese is melted, the inside is exactly where I want it.
-Hot dogs. Again, make sure you're set up with relish, pickles, kraut, maybe some chili if that's your thing. If you need advice cooking hot dogs then...well...