Here is what i have been doing for a decade and would receommend
1. Reusing plastic bags (i love cotton bags but not ideal). Fold and keep one or two in your pocket before you leave home
2. Support and use light software so you dont need to upgrade your gadgets (12y laptop i use)
3. Prepare and eat home cooked meal (its 360d in my life). Good for your health and the environment
4. Plant Trees. i plant one every month on average
5. Collect rain water and/or use less water
4. Prefer walking over any other transporation
5. Dont fucking care about trends.
6. Sleep 8hrs. less waking hours means less consumation.. lol
7. Prefer quality over quantity everytime.
8. Carry a water bottle (copper ideal).
9. fuck sugary drinks.