Hi, When writing my blog posts how should i go about linking to external sites, for example that i do not require that i link to. For example if i want to link to facebook, or bbc should i use no follow or should i not link at all.
No reason why you don't link to any site. Using no follow may not be a bad idea to preserve link juice.
If you include content relevant external links into your post, it will help search engines understund your content so will help to theme your page.