Go Meat Free
Eating less meat is the number one action a person can do to reduce our impact on climate and the ecosystem. Eating is what we do daily and changing what we eat will have a huge impact. Vast amounts of energy are used in producing grains to feed and then killing animals for us to eat. In fact, about 1/3 of all Greenhouse Emissions can be related to the food industry.
I grew up going to our relative's chicken farms and working in our family factory producing meat products. If the meal didn't have meat, it was not a meal. Over time realising the impact of meat, I started to replace one meal with veggie alternatives.
You don't have to become a total vegetarian to be part of the solution, but you will need to greatly reduce your consumption and start eating more healthy veggies instead.
Start by making a food diary of what you normally eat on a weekly basis. Food is like voting three times a day and start replacing meat with nice healthy alternatives.
There are billions of posts, books, articles on Vegetarian foods that I'll let you get on with.