A lot varies depending on the keyword and how competitive it is really
How many keywords?
I tend to recommend less than ten to start with, maybe a couple more for geo targeting, if you are chasing highly competitive keywords then less so you can focus more on the important ones.
Keyword type…, small caps, caps? Comma spacing, “ABC, ABC” or “ABC,ABC”?
I always use lower case and leave a space after the comma, I don’t think it makes any difference though.
Is important, there’s no hard and fast rules for it though, you have to experiment, a non-competitive keyword won’t need much density to do well, a highly competitive keyword such as “design” will need to get as dense as possible.
Extremely important, always has been, place your keywords as early as possible in the page title.
I don’t think this matters much or maybe at all, it might even be part of the EMD update.
As in META tag? A lot of people say meta tags are ignored but I still take the time to do them well, it’s just an opportunity to use keyword alternates from your page title eg “London web designer” to “web design company in London”
guest posting never get old but it should be done for loyal visitors more than just a backlink
reduce your page load speed and bounce rate
work more on getting high quality backlinks one page rank 9 is better than a 1000 backlink from 1 page rank
. Keyword should be 2 to 3 phrase
. Content should be fresh and innovative quality
. Keywords density should be 2 to 4 %
. Page title length should be 64 chracter
. Meta description should be descriptive and informative
Old SEO gone now don’t use exact match anchor text for your keyword, also don’t take links from irrelevant sites, go on quality not quantity, and guest posting and social media are the major sources of back links