In a typical Project Lifecycle, the initiation is in the form of an 'Expression of Interest'.

Whether it is internal to a business unit, or within an organization, or B2B (business-to-business) interface, or a policy roll out by the public sector department, or a collaboration between cross-border entities - as such, it could be as simple and private as an individuals study plans on one end - and may reach the other extreme of a mega project of NASA or World Bank - every project begins with an 'Expression of Interest'. In simple terms - it is the first idea, the first discussion, the first exchange of views, the identification of a need or a problem, a wish, a vision, a dream - anything that sets the context for an initial brain-storming and study of the subject matter.

Therefore, one basic skill any Project Management expert must have is to promptly capture the initial ideas and thoughts and inputs into a structured information form.

Here is a simple template for easily capturing data and information of a potential project. The form has pre-designed terms with adequate space to input the details collected and received.

For the purpose of PRACTICE - go ahead and keep preparing  one Internal Note daily on whetever new ideas and possibilities you come across. A few of those will certainly move to the next step! In any case, 'Practice Makes Better' - and so, in a short time one can become an expert in initiating a project - by simply drafting an Internal Note daily.

The reason this form is named "Internal Note" is that practices all around the world has shown that any new concept and idea or a possible opportunity is first validated by internal stakeholders - before they are taken to the wider and external stakeholders. So, in a project lifecycle - this works well as the first step. 

It is to be noted that the preparation and evaluation of an expression of interest may or may not convert into a project. That would depend on the feasibility study, expected returns and other similar factors. This aspect is covered in the next step of project management.