Can you do this as an exercise?
Everything that would ensure noting is traced back to you, dont you people watch CSI?
In reality I dont think things are as advanced and cool as CSI, AHA! We got a singe hair from you Bub, we linked you to the murder, doesnt happen in reality. If you're not seen by anyone or dont leave any digital traces connecting you to a person and you dont leave fingerprints you're pretty much clean.
If only Lt Horatio Kane or Dr Brennan + Agent Booth were real. It's easy to solve a murder when you invent it, but otherwise you only speculate and hope you find evidence to back it up.
A person needs a motive. Then they need...an idea...then they need objects to make the idea happen...things like gloves...
Even then there's a slim chance of success...so you have to be prepared to be caught...and suffer the consequences.
Kill someone, that should do the trick. 乂^◡^乂