A first aid kit should help you treat minor injuries and stabilize major injuries until help arrives. Make sure that you carry a triangular bandage, some pressure bandages and bandaids at all times. Bring insect repellant and sunblock. Know how to use your map and compass. Good sturdy boots with non-slip soles and ankle support.
Some people prefer gumboots if working in marshes.
Make sure they fit. Do not wear sneakers. Heavy wool socks to prevent blistering. Strong loose cotton pants help you move in brush and will not tear. Wear a belt.