Most searches for a supplier in this category begin with the wrong question. Buyers ask who is good, when the thing that decides the outcome is what they are asking the supplier to hold. Digital marketing is not one service. It is a bundle of quite different crafts sold under one label, and a proposal that covers all of them at once is very hard to compare with a proposal that covers three of them properly.
What a national digital marketing brief in Australia has to settle first
A national brief carries a problem a single-city brief does not. Your audience sits in a handful of dense metropolitan markets with very different media habits, plus a long tail of regional centres that almost every media plan treats as a rounding error. Before anyone quotes, write down whether you want one plan applied everywhere, or a core plan with a small amount of local variation, or genuinely separate plans by state. The three cost different amounts and need different agency structures, and a supplier will happily assume whichever one suits its bench.
The second thing to settle is who owns strategy. If you have a digital marketing lead internally who sets direction, you are buying execution and should say so, because paying an agency to rewrite a strategy you already have is the most common way budget disappears in the first quarter. If you do not have that person, accept that you are buying judgement as well as hands, and price accordingly.
Channel mix is a budget decision and it should be yours
Agencies are honest about their strengths in the room and silent about them in the plan. A firm built on paid search will recommend a plan weighted to paid search. A firm built on creative will recommend one weighted to creative. Neither is dishonest. They are describing the work they can actually deliver well.
Protect yourself by writing the mix yourself, as a first draft, before the briefing. Split the budget across acquisition, retention and brand in rough proportions you can defend, then ask each candidate to argue with your split and justify the change. The argument is the useful part. A supplier who accepts your draft without comment is either agreeing or not paying attention, and you will find out which one about five months later.
Be specific about what is out of scope too. Local search presence for multi-location businesses, marketplace listings, trade and retail media, and email lifecycle work all sit inside the digital marketing label and all get quietly dropped when a plan is written by a channel specialist who does not do them.
The agency fee and the media budget are two different purchases
The single most useful line you can add to a digital marketing request for proposal is that fees and working media must be quoted separately, with the fee expressed as named roles and their time rather than as a percentage of spend. Percentage-of-spend arrangements are common and not automatically wrong, but they tie the supplier's income to how much you spend rather than to what the spend returns, and that misalignment gets worse exactly when budgets grow.
Ask directly whether media is passed through at cost or bought and resold. Ask whether any rebates, volume arrangements or platform incentives exist, and require that the answer sits in the contract rather than in an email. Then ask for platform-level invoices to be available on request from the beginning, not as something you negotiate later when trust has already gone.
Three shapes of supplier, and the work each one suits
The digital marketing suppliers serving this country divide roughly into three shapes. Independent full-service firms carry a broad team and suit companies that want one accountable partner and do not have the internal capacity to coordinate several. Channel specialists go deeper in one discipline and suit a business where one channel already produces most of the revenue. Network-owned agencies bring scale, planning muscle and process, and suit larger advertisers with brand obligations and procurement requirements attached to them.
The failure mode is buying the wrong shape for the stage you are at. Small advertisers inside large agencies get junior teams and slow turnarounds. Large advertisers inside small independents outgrow the supplier within a year and spend the following year pretending they have not. Ask every candidate where you would sit in their client list by size, and ask who else the team assigned to you is working on.
Attribution arguments end when you agree on one number
Every channel in a digital marketing plan reports its own success using its own attribution, and the totals do not reconcile. Paid social claims conversions that search also claims. Email claims revenue that would have arrived anyway. If you do not settle this at the start, you will spend every quarterly review litigating whose numbers are real instead of deciding what to do next.
Pick one business measure that belongs to the whole engagement and is defined in your terms. For a lead business that is usually qualified enquiries and their cost, with qualification set by your sales team rather than by a form submission. For a transactional business it is orders, contribution margin and blended acquisition cost including the agency fee. Platform metrics stay in the report as diagnostics. They are not the score, and treating them as the score is how a plan drifts for a year while everybody reports success.
Reporting rhythm and the question that keeps a retainer honest
Monthly reporting is the default in digital marketing retainers and mostly performative. What changes behaviour is a shorter operating rhythm for decisions and a longer one for judgement: a brief weekly note on what moved and what is being changed, and a quarterly session where the plan itself is on the table. At the quarterly session ask what the agency stopped doing. Retainers accumulate activity because everything added last quarter is still running and nothing is comfortable to kill. A review that only adds is not a review.
Finally, agree custody in writing before work starts. Advertising accounts, the analytics property, tag containers, audience lists, creator agreements and any customer data live in accounts you own, with the agency granted access. In this category the cost of a messy exit is higher than in most, because the agency touches your ad platforms, your website and your customer list at the same time.
Narrowing a long list without losing a quarter
Two or three candidates, one written brief, the same three questions, and the fee and media split out in every response. That is enough to make the differences visible. If you would rather set out the brief once and receive proposals in a consistent shape, you can describe the work and collect comparable offers instead of running the same conversation several times.
If the bottleneck turns out to be one discipline rather than the whole bundle, compare the generalist against firms that do nothing but organic search or against teams built around social channels, and look at studios that rebuild the pages the traffic lands on if conversion rather than traffic is the constraint. For how this category is defined and what sits inside it, start with the overview of digital marketing agencies, and compare the local picture with the same category in another English-speaking market if you are considering an offshore arrangement.