Looking For A Better Tone

I've been playing guitar for around 2 years now, I'm not really that great mostly because I don't put the effort in to practice. I start feeling unmotivated because the music I like/listen to i try to learn and the tones are so off i quit.

Anyway my gear:
ESP LTD F-50 Floyd Rose Guitar - It's stock except i put a wooden block under the bridge, took the locking nuts out and tightened the springs up to get rid of the floating bridge.
Boss Metal Core ML-2 pedal - Completely stock, no changes.
Raven RG-20 Amp - Stock.

I listen to all sorts of things, Pink Floyd, Children of Bodom, Lamb of God, Disturbed, Red Hot Chilli Peppers, Slayer, and many more. Is there a good way to achieve an overall tone? Or even just getting the Lamb of God type of tone would be awesome.

I guess what i'm asking is what would be the most necessary thing in my rig to upgrade first? I've learned all i can about the gear i own played with the settings many times but I can never get the tone i like.

Thanks for all of your guys help,

- Quinn