There are general usability guidelines, which don’t much change regardless of audience/purpose etc. Most of these covers what is mostly obvious, but they can be helpful if you are not sure.
Slides are a good example of where, in my opinion, habit, a lack of planning and often appeasing a client rule the roost.
I don’t like sliders, at least as headers on pages anyway. I stopped using them by choice ten or so years ago. My logic was "If a message is important enough to be the very first thing a new visitor to site will see, you don’t want to then be immediately diluting that message by by replacing it with other messages every 5 seconds.
With some sliders you have one message over some sliding images, and the sliding images re-enforce the message, I’m cool with these. But those slides where everything; text, links and images changes, change I don’t like. But, I do loads of them as clients want them!
In my opinion slides came about because they added some movement to pages that until this point were more or less static, except for some dreadful animated GIFs. Nowadays, again my opinion, they are used by people who can’t plan a web page or make a decision on what is the single most important message they want to convey.
As I say though, none of this stops me using them, as clients love them. Some listen to common sense, most don’t, and on things like this I’ve long since given up trying to educate those clients.
Final comment on slides: When was the last time you landed on a site and waited for all the slides to come and go? There’s your answer!
As for B2B sites, these are a very different beast to B2C, and while I’ve made a few, they are not my forte. The first thing you need to consider is that a lot of your traffic might be desktop not mobile, so that can influence your design. After that, it’s again a case of understanding your audience.
In the last few years two B2B sites come to mind. One was for a chemical manufacturer who white labels commercial and domestic cleaning products. Their audience was buyers in places like tescos etc. I did a bit of research and found that it’s mostly the junior buyers who look over the sites, assess the company then push them up the chain to their bosses, who were typically chemists. So, I made that site to appeal to a younger professional audience whilst not looking garish to an older professional.
Then there was a software maker who needed a site to use as a showcase for their product on a marketing trip the US to present themselves to senior managers. This site was therefore ultra clean, pixel perfect (I hope), minimal clutter and all clearly laid out content.
As I say, in almost all cases your audience will dictate you’re design.