Sprint planning
Be realistic about what you can archive

The sprint planning is a session your team uses to determine what to build in the sprint. Your product owner should be able to tell the development team what he wants and why. Your development team should be able to tell if that's possible and how.
Go to: Points instead of hours | Neat Scrumboard

How many points can a team do in a sprint?
Giving ESTIMATIONS for each story in poker points

Estimations are super hard. In Scrum you only estimate small parts of your project making it already a lot easier. On top of that it can be a good idea to estimate your stories based on points instead of hours. A good tool for point estimations are scrum poker cards. Yes that is right, poker cards!

You don't like all that fysical stuff? Well, you can always use a dedicated online tool for planning poker, like this nice website called agilepoker.nl which is fully responsive and free!

Neat scrumboard means Higher velocity 
Yes, You do need a good lookin' scrumboard

So...you know what to build and your team is confident that it can make it happen. Time for a neat Scrumboard! I can't emphasize this enough but putting some time in the looks of your Scrumboard does reflect positive on your velocity. Your Scrumboard must reflect your progress during a sprint and if your board is clean and neat, it does do that job the best. Of course..this is also a team effort*

* you could try to make it an impediment so your scrum master will do some cleaning :)