A good 6L6 pair?
I mean, you're not giving me much info to go on here lol...
aside from using heavier gauge strings? what else can i do to get a better clean tone w/ just guitar---amp
Turn the amp off while you practice.
Work the guitar's tone and volume controls more while you play with the amp on.
Try playing with your fingers instead of a pick
Watch derek trucks play and try to sound like him (easier said than done)
Sell your guitar and get a cello or a tenor saxophone
Go to the top of mount Kilauea and give an offering of human fingernails to the yogi on top
Really, you'll have to give us more info for us to give you more specific advice...
So.....did you do it yet?