Progress Means Measuring Physical Percent Complete

The measure of progress in a project must be done through some form of Physical Percent Complete. If not, then all you're measuring is effort and the consumption of time and money. The use of Earned Value is one way to make visible Physical Percent Complete. One overview of EV comes from The Department of the Navy, which has many resources on the application of EV to projects

Earned Value Management is an effective management control tool, and it is important that Program Managers understand EVM as a disciplined planning and management system, and use EVM data in day-to-day program management. When used properly, EVM allows both Government and contractor program managers (PM) visibility into technical, cost, and schedule planning, performance, and progress on their contracts. This visibility provides not only insight to contract performance, but also provides data points to statistically estimate probable completion costs. The implementation of an effective EVMS is a required function of program management. It ensures that cost, schedule, and technical aspects of the contract are truly integrated.

Earned Value is not the only way. Scrum's measurements of velocity - if the units are calibrated in dollars and time rather than some cockamamie units popular by the extremist - can be equivalent to EV's Cost Performance Index (SPI) and Schedule Performance Index (SPI).
    This BTW is the source of many failure modes in projects

Failure to provide  units of measure meaningful to the customer

By meaningful I mean dollars and time. That's a meaningful unit of measure to a business manager.

Progress To Plan is How PM's Speak to Customers
    Trying to complete on time, working real hard, describing all the issues that have arisen since we last talked is not making progress to plan. Speaking about Physical Percent Complete is how good project managers talk to their customers. Without this basis of conversation, all other conversation are not about projects. They may be about something else, but it's not about managing projects.
    This doesn't mean there aren't many more aspects to successfully managing projects. The previous post list some of them. Others include all the softer sides of a projects, the political sides, the technology of the products, services, and tools and of course the general nature of business processes.
    But as a project manager if you can't speak in clear and concise terms, in units meaningful to the customer and the team about where you along the plan to successfully deliver the product, service and the business benefits - the other aspects of project management are moot.