#1
In one of the tabs I'm trying to play I saw the chord

x6888x

I'm still in the learning stages here and while x688xx is easy, its hard to fret 3 strings on the 8th while keeping my first finger on 6. Any particular way you guys would play that (finger positions, etc).

Apart from one finger per string, I tried this ridiculous way to bar the 8's with my other finger while keeping my index on the 6, but that didn't work very well.
#2
x1234x

Just like you would catch any barre chord.
But I suggest you to practice it by using just the index+ring finger, than index+little finger.
You will probably need it in the future.
"That was it, a nick. Now happily paid for. [...] It was decided that it was so far away in time and influence that...well, you only get caught when you're successful. That's the game". Robert Plant
#3
Use index for 6, and your other three fingers to hold down the 8. Use the inside part of your index finger to make the dead note for the e string, and your thumb or E string.