Need help playing trash and melodic guitar

Ok, no matter how hard i try i just cant get anything i play to sound like lamb of god, cradle of filth, or cannibal corpse. For some reason i cant do it. What should i do?

playing death metal is all about training, after you gradually work up in BPM's and mastered alternate picking, and master'd palm mutes and some harmonic minor scales, you will play any death metal song easily. But the number one tip i can suggest is mastering alternate picking first before any other thing, this gonna help you play faster and more accurate.