I have the good fortune of working with 1000+ brands on their paid advertising. And the greatest hurdle that all successful digital advertisers overcome is figuring out what they really want from their marketing efforts.
Most people know it, but only a few truly measure it. :)
A measurement framework is the best cure for this problem.
Here's a famous quote by my favorite analytics guru Avinash Kaushik.
There is one difference between winners and losers when it comes to web analytics. Winners, well before they think of data or tool, have a well structured Digital Marketing & Measurement Model. Losers don't. ~ Avinash Kaushik
Let's start at a very high level, what does your business want to achieve? It's important to have a clear understanding of this, if not you are unable to evaluate if the campaigns have been effective.
Understanding Business Goals
This can all depend on the business model you have. However, any business objective can be put under the following 3 categories
Increase Revenue
Decrease Cost
Improve Customer Satisfaction
You can have a subscription product like Netflix, or even have a very physical product like shoes or you can even be selling real estate, These objectives will stay true. Before we go to fixing objectives, Let's do a quick exercise. Can you bucket all the metrics you measure into the above three buckets? We can then identify and fill the gaps as we move along :)
Let's consider the example of an apparel eCommerce. What metrics do we need to measure? At a very high level, we want to know a few things
Revenue - What's your monthly revenue, what's the breakdown (Offline, Online, app,), Average order value, Items per customer, Return on Ad Spend,
Costs - Cost Per 1000 Impressions, Cost Per Click, Cost Per Conversion, Cost per thru play, Cost per Message,
Customer Satisfaction - Avg Ratings, % reviews/Customer, NPS Score, Brand Metrics,
This might not be everything but this is a start. How do we dive into a bit more detail? How do we map our marketing activities to the framework? Let's dive in.

Simple as simple gets :D
Now that we have a skeleton for the framework, next thing is to look at what KPIs and metrics to measure in order to get a good understanding of where you stand. The next step would be to do historical analysis.
A historical analysis will help you set benchmarks, and also will help you identify seasonality. Once we have this information ready, we know where we are, and also we know what needs to be done to meet our organizational goals.
And most importantly it will help you find the gaps in measurement. For example, your conversions might not be tracked on the site? How can we know if the campaigns did actually work to not?
A measurement framework needs to be followed by a good audit. It will help you understand the gaps in measurement and figure out a plan to track all relevant touchpoints of the customer journey.
Now lets' look at some of the essential KPI's we need to be looking at.

Are you measuring all the essential KPIs? more importantly, are all the KPIs that you are measuring essential?
It's common to be measuring vanity metrics such as page likes and engagement. Although this can be argued the best way to verify a metric is to ask these three simple questions from each metric.
By working to improve this metric
Will it increase my revenue?
Will it decrease my cost?
Will it help improve my customer satisfaction?
If it's a no for all three, forget about it. If your manager asks you to send a bunch of useless metrics ask the same questions from your manager or senior. They might actually have a good reason to be measuring vanity metrics ;)
Once we have this in place, we are ready to have some fun. Run some experiments, try a few new things and yeap measure the impact :)