Helpful links:

• Roguecraft 101, discussing the value of various stats (+hit/+crit/expertise), and the performance of various types of gear or talent builds for raiding rogues
• Aldriana's rogue gear spreadsheet, an Excel spreadsheet useful for comparing various DPS upgrades
• Dontmindme's rogue DPS spreadsheet, another spreadsheet, but with the ability to import armory profiles
• Shadowpanther's rogue info page, ranks all level 70+ rogue armor, trinkets and weapons using the AEP (Agility Equivalency Point) system. Good way to get a rough idea of how big an upgrade something might be. Use the spreadsheets above for quantitative comparisons.

Tips (in no particular order):

• To maximize your DPS never let slice and dice drop
• Never let your energy get back to full
• Don't die. A little less DPS is better than no DPS at all
• Getting to the hit cap is nice, but not necessary. Try to balance your increases to +hit and attack power.
• Crits are nice to see, but are not a true indicator of damage output
• For maximum personal DPS, go swords. For maximum raid DPS, go tri-spec, assuming nobody else in the raid has that spec.
• Gemming for PvE, unless you need to satisfy a meta gem requirement always socket glinting gems (orange +hit/+agi). The exception would be if you're at or near the hit cap, in which case socket a red +agi gem; the +agi will scale up with Blessing of Kings. If you have to meet a blue socket requirement try to use a purple +agi/+sta gem. If you're way below the hit cap, then socket a yellow +hit gem.
• Never gem for crit
• Do Heroic Magister's Terrace until you get the Shard of Contempt - ya rly
• Be Master Looter for Gruul, in case the Dragonspine Trophy ever drops... j/k ... sort of
• If you want to do well in 2v2 arena matches, partner with a priest, druid or warlock.
• Double Mongoose enchants.