How to Identify Project Milestones

"A project plan, according to the Project Management Body of Knowledge, is: "...a formal, approved document used to guide both project execution and project control. The primary uses of the project plan are to document planning assumptions and decisions, facilitate communication among stakeholders, and document approved scope, cost, and schedule baselines. A project plan may be summarized or detailed." ...
The objective of a project plan is to define the approach to be used by the Project team to deliver the intended project management scope of the project.
At a minimum, a project plan answers basic questions about the project:
Why? - What is the problem or value proposition addressed by the project? Why is it being sponsored?
What? - What is the work that will be performed on the project? What are the major products/ deliverables?
Who? - Who will be involved and what will be their responsibilities within the project? How will they be organized?
When? - What is the project timeline and when will particularly meaningful points, referred to as milestones, be complete?" [Project plan. Wikipedia]
The timeline diagram example "New business project plan" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Timeline Diagrams solution from the Management area of ConceptDraw Solution Park.

Timeline charts presents events and time periods on a chronological scale. They are used in project management to visualize project milestones and upper level phases, and show project progress.
"Within the framework of project management, a milestone is an event that receives special attention. It is often put at the end of a stage to mark the completion of a work package or phase. Milestones can be put before the end of a phase so that corrective actions can be taken, if problems arise, and the deliverable can be completed on time.
In addition to signaling the completion of a key deliverable, a milestone may also signify an important decision or the derivation of a critical piece of information, which outlines or affects the future of a project. In this sense, a milestone not only signifies distance traveled (key stages in a project) but also indicates direction of travel since key decisions made at milestones may alter the route through the project plan." [Milestone (project management). Wikipedia]
This timeline diagram example was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Timeline Diagrams solution from the Management area of ConceptDraw Solution Park.

"The RFP presents preliminary requirements for the commodity or service, and may dictate to varying degrees the exact structure and format of the supplier's response. Effective RFPs typically reflect the strategy and short/ long-term business objectives, providing detailed insight upon which suppliers will be able to offer a matching perspective. ...
RFP:
(1) informs suppliers that an organization is looking to procure and encourages them to make their best effort.
(2) requires the company to specify what it proposes to purchase. If the requirements analysis has been prepared properly, it can be incorporated quite easily into the Request document.
(3) alerts suppliers that the selection process is competitive.
(4) allows for wide distribution and response.
(5) ensures that suppliers respond factually to the identified requirements.
(6) is generally expected to follow a structured evaluation and selection procedure, so that an organization can demonstrate impartiality - a crucial factor in public sector procurements." [Request for proposal. Wikipedia]
The project plan timeline diagram example "Request for proposal (RFP)" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Timeline Diagrams solution from the Management area of ConceptDraw Solution Park.