Beginner tutorial for Sitecore8 developer
There is plenty of information regarding Sitecore in the internet for a quick start. I would recommend just few of them:
http://learnsitecore.cmsuniverse.net/
https://www.cmssource.co.uk/blog/2012/June/basic-sitecore-development-tutorial-part-1-introduction https://sitecorebasics.wordpress.com/2011/05/13/basics-of-sitecore-for-beginner-developers/
You will need to understand how to create pages, how data templates work and presentation details like layouts and renderings and other fundamentals
https://doc.sitecore.net/sitecore%20experience%20platform/creating%20and%20editing%20items https://www.cmssource.co.uk/blog/2012/June/basic-sitecore-development-tutorial-part-6-layout-and-sublayout-implementation
You will also need to find out some architecture basics about Sitecore, like content management and delivery servers and databases used for that (core, master, web). What is publishing and how it works, and why is it important.
http://learnsitecore.cmsuniverse.net/en/Editors/Articles/2009/07/PublishingAndVersioning.aspx
Also it would be very benefocious to understand Experience Editor (previously called Page Editor) and what are the particularities of creating pages to support it; as well as the advantages it brings to business users.
https://sdn.sitecore.net/upload/sitecore7/70/page_editor_recommended_practices_for_developers_70-a4.pdf
There are also some differences in MVC approach you need to understand before doing Sitecore with MVC. You need to understand View Renderings and Controller Renderings, as well as how the routing works in Sitecore MVC.
http://sitecore.unic.com/2015/06/24/the-sitecore-mvc-puzzle/ http://www.sitecore.net/learn/blogs/technical-blogs/john-west-sitecore-blog/posts/2015/02/how-is-sitecore-mvc-different-from-aspnet-mvc.aspx http://www.sitecore.net/learn/blogs/business-blogs/technical-trends/posts/2012/06/mvc-and-sitecore-651-overview.aspx
There are other aspects of Sitecore you may need to understand: workflows, caching, indexing, pipelines, events, sitecore security model etc. Generally, speaking, the question you asked is to wide even to answer that by sharing the links. But those I quoted is enough to start
There are many YouTube channels that may be much more helpful for the beginner:
https://www.youtube.com/watch?v=yytEQnJpF1I
https://www.youtube.com/user/mastersitecore
https://www.youtube.com/user/sitecoreceptraining
https://www.youtube.com/watch?v=AQGtFA8Ud2Q&list=PL5QMcxdLbK7gGSTcPZJal2i5GHu1VHrl4
Also, if you budget allow that, you may consider to take official training courses - they are quite helpful for the beginners. http://www.sitecore.net/services-and-support/training.aspx