We'd have to know what kind of fellowship you are to advise you on the kind of "welcome" overview you would want to write. There isn't one that fits all memberships. Some are casual. Some are 10 chest plus fellowships.
What kinds of boosts do you need? If your fellowship is low in marble, for example, you could list that as a critical need. Marble players might be likely to join. The downside is that it might put off people with other boosts.
There's no template ... you just have to figure out what kind of fellowship you are and what you are looking for in a new player. Remember to gear your Overview to the kinds of players who would be interested in your fellowship. No sense in looking for a high level, million plus player if your team gets only 5 or 6 chests a week. Likewise, if you are a high level fellowship, you may not want to take everyone who asks.
Good luck, and congrats on being made archmage.