SmallP - 8:24 am on Aug 16, 2013 (gmt 0)
Pretend it is 10 years ago and no-one is paranoid about links.
Ask yourself "Why am I linking out?"
The answer should be "Because this link will be useful for my visitors".
Now link out in the most natural way possible. Whether that will be by keyword text or domain name will depend on the context.
Link with the word "here" if it is appropriate. Link with the domain name if you want to. Link for your visitor and link through the word/words that makes the most sense. Personally I think it is polite to let your visitor know that you are sending them elsewhere too. "You can find some excellent examples of this at this site" or "If you would like more along these lines, there are some excellent resources here".
We are pretending it is 10 year's ago, remember. Links are for traffic, not for ranking. I respect another site, I send them my visitors and some traffic.
Use "target="_blank" as another courtesy to your visitors. It makes it doubly clear to them that they are visiting another site, and allows them to make their own decision as to when to leave yours.
It was simple 10 years ago.
Now fast-forward to the present day.
Ask yourself, "Am I able to maintain and check this link regularly?"
If you have a 20 or 200 page website, you probably don't have a problem.
If you have a 10 year-old, 10,000 or 100,000 page website, you probably do.
These days I might no-follow links on all but my main pages because I'm just not sure when I will be able to check them again.
Now go back to the original question, "Why am I linking out?" If the answer is "I hope it will help my ranking somehow" then just don't do it. DON'T.