Down under you will find great links. Some of them you should be using a actively and other are great sources to for knowledge.
Amino.dk – Danish site, for entrepreneurs.
Blogger.com – Googles blogging platform. You can have as many blogs for free as you want.
Coursera.org – Free online courses available from the best universities worldwide.
Calendar.google.com – One of the best free calendars for desktop and smartphones.
Drivhuset-easj.dk – An environment for danish and international student-entrepreneurs in Denmark.
Dynamicbusinessplan.com – Makes it easier for you to make a businessplan by giving you tools and information.
Entrepreneur.com – News site for entrepreneurs.
Facebook.com – A great social media, with users worldwide.
Instagram.com – Social media where you can share pictures and small videos.
Linkedin.com – A professional social media.
Nielpatel.com – A e-commerce expert, with great tools, articles and more.
Ritetag.com – A site to look up the best hashtags.
Startupsvar.dk – Danish site, where you can get answers on the 100 first questions new entrepreneurs have.
Strategyzer.com – The businessplan, taken to the next level by Alexander Ostawalder.
Themeforest – To find amazing themes for your website very cheap.
Thomasbigum.dk – A social media expert. Great at what he does. Just in danish.
Trello.com – An awsome way to manage different tasks.
Unoeuro.com – A cheap but good host and a place to buy domains.
Youtube.com – The site with videos of things you couldn’t even think about.