I have seen many many reports of people abusing their guildmaster status to con people of items, along with reports of people snatching and running because they want to make the quick profit. Its their loss since the MU society will blacklist them and keep them down doing childsplay, but it does suck to lose your cherished earning to scum. Therefore, this guide is made to prevent being scammed.
Step 1: Finding a Guild
This is where it all starts. "What guild should I join?" is the big question. There are many guilds, but the real guilds are hard to come by. Real guilds are guilds that act as family to each other, fully trusting each other and working together as a collective. Real guilds bring many benefits to people, as the trust and team sieges on mobs helps the entire guild advance. Real guilds also support one another, when making new characters... or reobtaining a key mob spot for someone... or simply enacting revenge on a punk that picks on the weaker. Whichever the reason, the guild would fly to each other's aid. Just remember, though: pick a guild that values the entire guild as a whole instead of a guild with people who just want a name.
Guildmasters that require a "down payment" of jewels, zen, or items are usually scammers trying to take advantage from others. They know people get desperate to belong in a guild, and thus, capitalize off it. Don't let your desperation to belong get to you. Find a guild that you believe you can trust, as well as meet the Guildmaster's requirements to join. Also, respecting guildmates of another guild can give you big positives to join the guild.
Step 2: Starting in a Guild
This is where you put your worth to the test. Guildmasters want to see how well you perform to determine what to do with you. Experienced Guildmasters can easily give the executive orders and organize the guild to benefit to maximum performance. Your power is only one part of the test, as that shows where you should be in training. The other tests are trust and support.
Trust determines how well you can rely on the guildmates. This doesn't mean you go and donate all your blesses to everyone. Simply throw any spare items you dont need to guildmates that need them. If you see that a DK member needs a SS+skill, and you find a SS+12+skill but don't need it, be generous and give it to the DK. Jewels should only be given to the guild in some sort of treasury, with much trust put into the treasurer. Only spare jewels that you know you don't need. If you need to get an item because your current item is obsolete, then you can hold onto your valuables safely to get the item. The guild might even lend support to obtain the item. Just remember: spare only what you don't really need. Guildmasters respect guildmates that donate to the guild and its members.
Support determines how you look after your guildmates' back. After all, there are many soloers and other guilds out to get spots. If a guildmate can't train because some KSer keeps taking the guildmate's kills, and the spot is a key mob spot, bring support to the guildmate to wipe the KSer out. So you become a warning, or a murderer, or even a phono... who cares. Showing you'll risk your ass for your guildmates is what Guildmasters respect because they know they can count on you to bring a helping hand. Supporting the guild also means joining guild wars and covering them incase of a non-guild party raid.
3: Growing with the Guild
As you hang around with the guild and improve, many challenges await. Killer guilds, uber monsters, and big drops. As long as you keep the values of trust and support, you should have no problem with the guild. Guilds are like families. The bonds between the guild members will grow over time. Don't rush the development of these bonds, cuz that never gets you anywhere. You'll gain the guild's trust, support, and respect in due time.