i have a business and a side blog on the website. is it fine to turn my blog to domain.com/XXX instead of  domain.com/blog/XXX? does it in anyway of these affect the SEO?

Hi i am a real newbie to this and i hope for a guide on how to do this. I seen a few moz post and is quiet confusing hopefully somebody able to explain it in layman terms to me. I would like to  301 redirect this way, both website contain the same niche. oldwebsite.com > newwebsite.com and also its pages..... oldwebsite.com/test >newwebsite.com/test So my question here is i would like to host my old domain and its pages in my new website hosting in order to redirect to my new domain and its pages how do i do that? would my previous page link overwrite my new page link? or it add on the juice link? Do i need to host the whole old domain website into my new hosting in order to redirect the old pages? really confusing here, thanks!

Hi guys, im here to ask based on your personal opinion. We know in order to rank in SEO for a site is to make authority contents that interest people. But what would you do to increase your ranking of your site or maybe a blog post? leaving your link on blogs comment seem dangerous, nowadays. Is social media the only way to go? Trying to get people to write about you? what else can be done?