Just a couple of links I've found handy:
Upgrade your account for free - this will expire when open beta starts and they're accepting payments, but if you plan to get a paid account and want to import all your icons, it's handy.
Import your LJ - imports icons and comments as well. (No one can see filtered entries until you set up your filters on DW.)
Change your style - if you don't want to do much work, you've got two options right now, Negatives (the default) and Zesty. (You can set the reading page in Zesty to be expanded by default by clicking on
customize your theme.) If you're feeling more ambitious, you can
import/customize a number of LJ styles.
Find communities - that's been pretty up-to-date so far.
Cross-post to Livejournal: will (hopefully?) be working by the end of the month, but isn't right now. If you want to use a client to make that easier,
here's a list of which ones work.
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Also, this doesn't apply to me and I don't know if they'll keep giving out invites in exactly the same way, but right now,
existing users don't get more invites until all the ones they had have been redeemed. So if someone sends you an invite and you don't use it right away, there's a chance they may be silently making sad faces in your direction but are too polite to bring it up. (Probably not a common issue at the rate people tend to jump in, but not something you'd necessarily know if you're not reading dw-news, so I thought I'd mention it.)