Do read leveling guides
WoW Insider has some great leveling guides for each class. These guides have collected everything special your class can do and should know for specific level ranges. You will often find me enthusing about Jame's leveling guides as well, particularly his Horde one. The maps and efficient quest groupings make this guide invaluable to the casual player.
Don't pug instances
Completing instances with good groups can be a great way to level up and get appropriate gear for easier questing. Running instances with pugs are most likely to be time consuming, frustrating experiences that will take up all of your play sessions and then some. There are plenty of quests that can be soloed from 1 to 70 and that way you are the master of your own time.
Do maximize your rest
You of course know that logging out in big cities and inns is the smart thing to do. Also, do any crafting or chatting in these places so that you are accumulating more rest during your non-questing time. If you are trying to level up multiple characters (I know some of you are afflicted with altitis), swap between them so that you only play the rested ones.
Don't go AFK in contested areas on PvP servers
Captain Obvious says, "Duh!" Of course, we casual players are well aware that real life interferes when we least expect it and the resulting deaths just can't be helped. If you can, however, try to get to a safe place before going AFK or else expect to face a scene similar to the one pictured above.
Don't worry about revenge
During the lazy days of summer, logging off to get your main and thump the twerp who just thumped you can be fun and rewarding, in an eye for an eye kind of way. But now that Wrath is almost upon us, if you really want to level quickly, it's best to just brush yourself off and continue with your questing.
Do level your professions as you go
Now that Gathering Professions give you abilities that help you in battle (I adore Lifeblood), there really is no reason to not level up a gathering profession (or two) as you go. Leveling the crafting professions can also help you keep current on gear which only makes questing easier. But I also recommend First Aid and Cooking as well. The quests at skill level 225 for both of these secondary professions give a lot of experience and having extra bandages and food buffs certainly isn't going to slow down your leveling. The farther you are along on your professions when Wrath hits, the more you can take advantage of the new benefits the expansion brings.
Do complete the quests when they're green
I'm sure you're OP and can handle the orange quests, but completing quests when they are green is faster than completing the yellow and above quests. The mobs go down more quickly and you are able to handle more simultaneously. It isn't always possible to stay ahead of the quests, but when you can, do.
Don't sweat the deadline
If you have played any MMO from the beginning or this isn't your first expansion, then you already know that the first few days are always rocky. Even if the developers have done their job perfectly and the hardware works without a hitch, there will still be dozens of people in every immediately accessible new area. They will be lagging the same zones, camping the same spawns and gathering the same resources. Do you really want to be hanging out in the DK starting area listening to the ramblings of Dkpwnsu, Dethknyte and Arrrthess? Waiting a day or two for the masses to race through will probably enhance the quality of your playtime quite a bit.
Do enjoy the journey
If you don't even come close to reaching your level goal by the time you are ready and able to play the expansion (I won't), don't be too hard on yourself. I think most casual players know that it's the journey that makes this game so much fun. Racing through the new content so that you can run the same Battlegrounds, Instances and Dailies over and over until the next expansion is not necessarily the best way to maximize your fun. Stop and smell the Talandra's Roses. I know I will.
WoW, Casually is a column for those of us who are playtime-challenged and proud Welfare Epic wearers. If you have questions or tips about how to get the most out of your limited playtime, please send them to Robin.Torres AT weblogsinc DOT com for a possible future column.