There are many different way to pull as a warrior. I am going to go over a few of the here and talk about their advantages and disadvantages. This guide is for pulling trash specifically.
1) Ole faithful a.k.a the ranged weapon pull: This has been the method of pull for most of WoW. It has changed quite a lot since the expansion with the additions of the Warbringer Talent and the Heroic Throw talent. Some tanks prefer a thrown weapon because of the short throw time on it. I prefer my gun because it has such tankalicious stats on it. I still use my gun for pulling, but it is less than it once was. Usually I use my gun to pull in one of two situations;
a) Heroic Throw is on cooldown
b) I am gonna burn down a melee mob first. In this situation I will gun pull the melee mob followed by a heroic throw on the caster to get him into AOE tanking range.
2) New and Hot a.k.a Heroic Throw: Heroic throw is a beautiful thing. If you are specced into gag order then it will silence a mob and cause casters to come right to you. It also does a decent chunk of damage and gives you a threat boost right at the beggining of the fight. The biggest problem is that it has a 1 minute cooldown which means it may not be ready for the next pull. This leads to my favorite pull method.......
3) ZOOM ZOOM DARRAXUS SMASH pull: This pull is brought to you by the warbringer talent and is my favorite pull method. It consists of me charging into combat and thunderclapping followed by a shockwave. Bam instant AOE threat and your DPS can blast them to smithereens. The one disadvantage to this happens if your healer insnt paying attention and 4 mobs beat you into a pulp.
4) ZOMG I IS TEH UBER pull: This consists of doing all of the above. Fire the gun, heroic throw, charge. Show your mad tanking skills.
As always, when pulling keep in mind your surroundings. Dont be a nub and pull more that you can handle. Make sure to LOS when you need to. Charging in is the most fun (not to mention it generates lots of tasty rage), but sometimes it just may not be practical.
One more small tip. In fights where you get knocked back or thrown (Archavon), you can charge in mid flight and it looks like you are charging in from the heavens. Gotta be quick with it though or you will go out of range.