Need advice on socketing, please...Follow

Check out Xordon's sticky post at the top of the forum titled, "Gear List: lvl 70 and Kara gear check." After the gear lists you'll find a list of gems for each colored socket, with links to describe what those gems do.

That being said, you describe your usage as being both DPS for farming and mining, and tanking for 5-man instances. Are you planning to use the Bold chestpiece for both purposes? From a stats perspective, the Bold chestpiece is primarily for tanking - the +DEF and socket bonus for DEF implies that. You might be better off tossing tanking gems in this piece and finding a separate piece (with better boosts to crit, hit, etc) for your DPS needs while farming.

For tanking gems, I like the Enduring Deep Peridot for the blue slot, which gives a nice boost to def and stamina. For the red slot, I like the Shifting Shadow Draenite, which gives you boosts to agility and stamina.

Cheers,
Jorge