More than plugins or strategy, you need good, quality content on a blog. There are a lot of subtle factors in SEO that will affect your rank more than your good intentions and plugins... relevance...
The simple answer is... if your only inbound links are also outbound, you're linking to them, they link to you, it looks to Google as though you are trading links (reciprocal linking). You need some...
Well, if nothing on your site has changed, I would be concerned that the host has some kind of server issue going on. It bothers me (and you, obviously) that they can't tell you where it's coming...
Think less about what you like or prefer and more about your reader... is there some value to them in you linking back to sites that link to you? If someone likes your site and links to it, it may...
You mean your conversion is dropping? Are you switching the ads up, how big is the area you're targeting, how long has the campaign been running? Could be getting stale, or the opposite, if you...