You will not find this guide on restricted realm, you will only find it at www.briankopp.com and it is by far, the best there is for alliance in World of Warcraft. Well lets start out with the simple grinding vs questing. Many people will argue that grinding is the fastest and many will argue questing is. I'm telling you that questing is. In rare cases grinding is helpful though. WoW is designed with so many quests throughout it. This was done so you were not bored grinding a whole lot like a lot of other MMO's. Questing by far blows grinding away in speed and boredom because you can grind stuff for quests while you're doing 2-3 quests at once. The times I was talking about grinding being faster are like in my guide at the end of 39-40 in STV where it's more efficient to grind than to do quests that won't get you to the desired level without some grinding. Also 59-60 we run out of quests. Sure you could do some outlands things but I still suggest not doing those until 60.
Instancing is generally a bad idea if you're trying to speed level. If you can get a group you know is good and won't wipe, it can be highly effective and fun. It's not worth doing every instance besides the thrill of seeing them at least once. I've still only done 2 instances in outlands so far because I get so into the questing in outlands. Other than "Knowing" your group will not have a problem, you should stay away from instances unless you don't feel like doing some grinds. The best things to grind are squishy mobs. These are ones with low hp and armor like mages. (You will learn much more about them in Brian Kopp's 1-70 Alliance Guide.) For example in outlands, near the teleporters on the east of the zone, are wraithbringers and such. These guys drop so fast and give normal loot and xp. The squishier they are, the faster they drop meaning more xp and money in less time.
I've made my guide to be pretty much solo besides the exception of Uldaman and 2 instances in outland that I say to do because there is a lack of quests in those spots that it's either do them or grind. Solo leveling is faster xp wise than group leveling because you have to split the mob xp. I am in the process of teaching my wife to play WoW and we're actually doing good on the xp according to how I wrote my guide. In spots we fall behind due to it but the mark is pretty close even with the half mob xp. I tried to do aoe grinding before but I just can't get it with my mage. I can't keep stuff away from me and I just get owned. I've seen people do it a lot and it works great. Nothing like emptying your mana fully into 20 mobs at once and then just resting and doing it again.
Now for professions, if using my guide, and you're speed running, you should only grab mining and skinning but at least get skinning. You can make a ton of money selling all the skins you get and it's extremely easy to level up. I can't really say what professions to get for money because I was never good with making gold off professions. First Aid is a must though. You need to get it whether you're a priest or rogue.
As I state on my itps page, gear is not important. Most people think you have to do every instance to get that awesome blue or all the group quests to get nice things. There is no reason to buy epics before 60 either. The reason being because a lvl 20 sword can do almost the same dmg as a lvl 40 sword because the dmg output is dependant on your skills and stats increasing every level. I've used low lvl 20-30 weapons and armor many times until the 50's and never noticed much difference. The only time you should get the best gear is if you're making a twink of some type. This is easily proved if you have a 60 in basic items and a epiced out character. The tweaking difference can be insane but it's not worth the trouble to be your absolute best for the entire leveling process.
Some things to avoid would be, of course, watching your pulls. Don't pull more than 2 things at a time if you can help it. Most classes can't handle more than 2 at once. You should also avoid grouping for the fastest leveling. There are times when you shoul group like at an overpopulated named mob for a quest so that everyone isn't trying to fight for it. If you're trying for the fastest time then avoid wasting time. Don't do BG's or go to the AH, use an alt, and don't sit around idle. Log out if you have to go smoke or something. Those 5 minutes here and there can add hours onto your final time.