If you want to talk about personal waste, the problem is two-end: reducing consumption (new stuff) and reducing disposal. Some plastic wrapping, some packaging and single use items are required in some applications (e.g. for sanitary reasons), but we can find alternatives (e.g. bamboo biodegradable cutlery) and look to use longer lasting items over single use. The second is the lack of segragation of waste streams and appropriate facilities to reclaim material from waste. Even if something is biodegradable, if it ends in a landfill it can release methane or if burned it releases CO2. Many landfills have most of their emissions coming from organic and yard waste, and diverting that to compost, mulch and natural gas digester projects.
There are a lot of problems but there are also a lot of solutions. You will have to set aside a level of waste you are willing to accept, and work towards places you can improve or propose items or support efforts that can help. Zero waste for everywhere and everything is an impossible goal that strictly pursuing that will achieve nothing but make you depressed.
For restaurants specifically, when you eat out you can go to places with washable plates and cutlery instead of paper/plastic ones, or for the cheaper end, ones that use bamboo cutlery instead of plastic.