Walk through a mall or something (to get people's dna, therefore to find your dna will be like finding a needle in a haystack)
Wear gloves to prevent fingerprints.
Enter victim's house with skeleton keys.
Chloroform the person (less struggling)
Since they're unconscious, you'll be free to stab them in an angle that will make it look like a suicide.
After leaving, re-lock the door.
There will be no evidence of breaking in.