It is a quite tiring process to do a selection of so many digital marketing agencies which will usually present more or less the same thing and leave you confused if you cannot dig deeper about them.
Here are some tips you can do for choosing a digital marketing agency:

Big Agency VS Dedicated Team
“We are big agency from big multinational company” This is a typical statement delivered by some agencies when trying to distinguish themselves from other agencies. While in fact the bigger the agency, the more clients they have, the harder it is for them to give the best service to the clients because of the limited resources. Besides, from the investment side, you apparently also have to compete with other clients to get higher priority. So always focus on the special team they provide for you rather than merely focusing on the company in general. Ask about the structure, workflow, and background of the team personnel that they provide for you.

The Team’s Background
Bringing in expatriates that claim to be experts in the pitching process is also one of the weapons often used. Unfortunately, these experts usually only appear in the process of pitching or party. What you need to dig deeper is the calibration of knowledge, skills, experience and communication of the agency from the top level to the operational level. Oftentimes there is a high calibration gap of knowledge, skill, experience and communication in the top level, manager level and operational level at an agency. When it happens, it will usually lead to an unfavorable work process because what the top level is communicating cannot be executed by the team. You need to observe the profile of each team that will work with you, whether they have the experience, skills, and knowledge you need to handle your campaign.

The Clients’ Profile
Some companies usually avoid agencies that are handling their competitor companies. For large companies, it is usually a definite rule, but if your company has different priority about it, there is no harm in going through the profile of the clients they have handled. If they often handle clients in the same industry, it means they have got their chance to learn from previous campaigns about which one works or does not work and so it becomes a useful input for your marketing strategy. Surely you can protect your marketing strategy by asking them to sign an agreement, and as professional agencies, they will certainly maintain their clients.

Clear business Model
Especially in digital marketing, each agency’s business model can be different from one another. Some apply per-project fee, per-service fee, hourly rate fee, retainer fee and so forth. Do not hesitate to talk about the details of the business model they offer so that both parties can get a good deal from the start.

Technology Utilization
A digital marketing agency is certainly inseparable from the utilization of the technology. Explore whether the agency you choose keeps abreast of the technology that supports your digital campaign later. For example, if you need an agency to create your company website, ask what kind of technology they are using and why?
source :
dailysocial(dot)net/post/agency-101-memilih-agensi-digital-yang-tepat-untuk-startup-anda