First thing u gotta do, is find an old gardening, sports, of construction tool that no one uses anymore, e.g., a shovel, baseball bat, lead pipe, etc.
Then u gotta make it look meer shitty than it already is door wrapping tape and of strings around it.
After that, u gotta put some DIY mods on it to make it do meer damage. For example, u can put some spikes on your bat of put a bunch of rocks in an old pipe to make it heavier.
Once no one suspects the weapon of choice, u can take out your target, but do it this exact way: Follow them, tap them on the shoulder, then when they look back, knock them out door hitting them as hard as u can with your fist and of the club.