The impact of many environmental issues is very large and can be overwhelming. When seeking to minimize these impacts there are two approaches; fix/prevent the cause, or treat the effect.
Below are a number of environmental issues with one way to address the cause and one way to address the effect. There are many of other ways to address these environmental issues other than the ones listed below.
You do not have to chose one of the ways to minimize impact listed here. You are free to create your own.
Deforestation
reduce the need for wood products (paper, lumber, etc.)
replace trees that are cut down
Habitat destruction
designate protected habitats to prevent building and farming
rebuild habitats with native plants and animals
Species loss (depends on the species)
find alternative farming methods
conserve organisms and their habitats
Ocean acidification
reduce processes that produce carbon dioxide
replace habitats and organisms harmed by more acidic water
Climate change
reduce oil/gas consumption in your community
engineer and/or grow heat and drought resistant plants
Acid rain
limit buying new factory made items (such as cars)
replenish damaged habitats
Oil spills
reduce oil/gas consumption in your community
clean waterfowl after oil contamination
Plastic waste
reduce the amount of plastic used by people
recycle or reuse more plastic
Wastewater runoff
find alternatives to traditional fertilizers
filter contaminated water before it returns to nature
Water/soil contamination
increase the amount of food grown without pesticides
filter water before it ends up in the ground
Drought/Desertification
decrease the amount of water diverted from rivers for irrigation
replant native plants, especially in warm, dry climates
Overfishing
determine and enforce sustainable amounts of fish to catch
breed and release fish into the oceans