one thing to NOT do is farm until u ascend, or are at least lvl 20. get to know the trade system of the game, and make some good deals. and example of what not to do is what my friends guild did. they went to lions arch, killed things around there together and tryed to make as money as possible. it took them a month to get the 125k (about) to buy the guild hall. I, however laughed at them as i made 225k in 3 hours of trading. so my advice is to beat the game first, as a guild hall is completely useless until you are lvl 20
Derrtyboy is right. A guild hall is completely useless until you start getting 8 lvl20 characters on at a time.
The best way to grow a guild while only getting good people, is to invite nice people who you form a PUG with. If you start a new character, you can group with people who just got the game and don't have a guild yet.
Also, get a Vent/TS server. People get so much friendlier with each other once they can actually talk in realtime. It's free to get a server (up to 8 people on Vent or 16 on TS) and anyone with half-way decent cable or DSL will have the bandwidth to run it.
Getting a hall is one thing, being the best is another. A hall - get your members to farm 5k daily until you get one. Simple as that. As for being the best, I can't help you there.