Self Organised Team

Reverse their questions and let them decide.  Stop yourself as the SM from making decisions for them.  Ask them how they believe something should be done. 

In addition to what Scott mentions, an impediment isn't an impediment if the team can solve the problem themselves. Use all your Scrum Master powers: empiricism, support, coach, facilitate, Sprint Retrospectives, time boxes, remove impediments, teach. But don't resolve unless it is an impediment.

I have a tattoo on my arm that reads "take it to the team". I highly recommend all Scrum Masters use that motto. Change your mindset to trust that a group of individuals' collective wisdom and bottoms-up intelligence are much greater than yours alone. And that they are more likely to buy into their own solutions and see them through than a solution prescribed.

As @ Scott Anthony Keatinge said, don't let others make decisions for them.

You should be focusing your attention on the organization outside of the team to help them understand the benefits of a self-organized team and how their actions will need to change to support them.  Encourage the team to make decisions on their own and not to expect or ask others to make them. Encourage everyone else to provide the team all the information known because no one knows what information will be important to the people doing the work.  Also encourage the team to be open about any information they have or gain.  The bilateral unfiltered sharing of information is one of the keys to teams being able to self organize. 

Remind everyone that some outcomes will be different than expected but the only failures are when no one learns from the unexpected outcomes. 

Do you have any practical tips or ideas to achieve self organisation?

It's a skill that has to be learned. A good Scrum Master will create bounded environments within which people can then take collaborative action.

Timeboxed activities, with a clear goal to aim for and rules to help people focus, are a good means of cultivating self-organization. Initially, you can't just leave a team to get on with it, because they don't know how to self-organize yet. This means you'll need to shine a light on potential issues and the likely consequences of their choices. A good Scrum Master will reveal but not resolve.