The internet is subject to perpetual change. Some of my advice has been updated from sermons on the preceding blockchain, and even what I write here may need to be adapted over time, too. Just keep in mind the principles of good netiquette, and you can navigate these changes.
There was a time when any posts above four per day earned decreasing rewards automatically. This is no longer the case, but I still recommend writing no more than about four posts per day. Concentrate first on quality, not quantity, and you are more likely to find a bigger audience.
Churning out a deluge of low-quality posts does not build an audience you want to have. It may even result in addition to one of the blacklists for downvoting.
With that said, if you are a prolific writer on a variety of topics, this is by no means a rule set in stone, and it may be to your advantage to postmore often. However, I strongly advise taking a slow pace and starting a list of posts you would like to publish later. Writer's block and blogger burnout will strike almost all of us. It can even be handy to have a folder of pre-written material on your computer ready to upload in order to even out your output, and PeakD has a handy post scheduling feature.
Reblogging is a way to share and promote content you like from other creators. Once upon a time, all content created or reblogged appeared on a single feed. At that time, I advised restraint. I still do not advise excessive reblogging, but I am less certain where excessive belongs in the sliding scale of content sharing. Reblogging can help promote content that otherwise may be hidden in a community feed others may not normally visit, so it is more beneficial than every before to the content creators, too.
Just remember that you do not need to ask permission in order to reblog someone else's post, and you have no obligation to tell them in a comment. That is now part of the update system anyway, and you want your comments to help build a meaningful conversation.
Cross-posting is a relatively new issue following the launch of the communities feature, and I am not sure what the best advice would be. Community administrators may have differing policies about what should be cross-posted in their feeds, and not everyone uses PeakD's cross-post tool.
Hive 1.0 is now under papal excommunication, and I do not advise cross-posting between chains at this time. Besides, the censorship code there may hide your content anyway.
I would therefore like to open this subject in particular to congregational discussion in the comments below. What is your opinion? How should this be handled? Are there changes coming to the site that affect how this will be managed in the future?