1) Pack In Pack Out. Many places offer lots of trash cans but that might give people the impression that it's okay to bring lots of stuff to the beach or park that's going to be trash. Some of it is destined to be litter also. Plan ahead and pack reusable items that you want to bring home and use again.
2) BBQ. Everyone loves a good bbq, right? If you are having it at home use the regular plates, utensils and glasses if possible - and have the kids help with the dishes! If you are headed to the beach or park, bring the reusable plates and cups. If you must choose disposable, look for a good paper option.
3) Bags. Leave the plastic bags at the store. Nothing says 1990's like bringing a plastic bag to the beach. You don't need a dedicated beach bag, most reusable bags will fit your towel, reusable bottle and other essential items.
4) Cups. Look around the beach or park on a busy day and there are lots of cups in people's hands. Plastic and foam cups are so cheap that people don't put much value in them so they are thrown away or littered without much thought. Invest in some reusable cups or utilize your reusable bottle. In addition to reducing plastic pollution, you could save money in the long run.
5) Everything else: Avoid the foam coolers and other cheap items that you plan to use for a day or less because they will likely break and be discarded. A $5 chair or umbrella is not likely to last through the weekend. Check local thrift stores, resale shops and websites like craigslist for quality items at a good price.
Have a blast this week and enjoy your local beach, park or favorite place!