When you navigate to your SEO action list you will see that the actions are ordered by priority level; high, medium and low.
These are based upon which actions are going to generate you the best return (for your efforts) in the shortest time possible.
We would advise that you prioritise your SEO actions upon the order in which we display these, as this is based upon our vast experience in delivering SEO for many, many websites.
However, this does not mean that medium and low priority tasks are not important! These will also greatly contribute to your overall SEO performance, so don't ignore these.
Just complete them once you've completed the high priority tasks first!