Give an architect an RFP and the first instinct is to start designing. I understand it. The design is the interesting part.
In a large transformation deal, though, the solution is one dimension out of five. If you only look at that one, you can produce a very good answer to the wrong question.
Here are the five I try to read in the first few days.
1. The business case
Someone on the buyer's side has to defend this spend. What do they need to show, and to whom?
It might be a cost target, a control problem, or a deadline set by an acquisition. Whatever it is, it tells you which parts of your response will be read closely and which will be skimmed.
2. The architecture
This is the familiar one, with a twist. The question is not what the best design is. The question is what fits the estate they already have.
Decide early whether you are proposing an incremental path or a full transformation. Each one leads to a different solution, a different price, and a different risk profile. Mixing the two without saying so is a common way to lose.
3. The commercials
The pricing model shapes the design more than most architects admit.
A fixed price pushes you toward standard components. An outcome-based model pushes you toward whatever you can measure. If the commercial team and the solution team work separately until the last week, the response will contradict itself.
4. The delivery risk
Ask who will build this, with what skills, by when. A solution that wins the evaluation and cannot be delivered is a problem you have sold to your own company.
Name the risks in the response. Buyers trust a team that sees the difficult parts.
5. The people who have to say yes
A CFO, a CIO, and a procurement lead read the same document with different questions. One wants the return. One wants to know what it does to the landscape. One wants comparable numbers.
Know who is in the room, and make sure each of them can find their answer quickly.
Why early matters
Each dimension is manageable by itself. The trouble comes from the contradictions between them. A design the commercials cannot carry. A timeline that delivery cannot meet. A business case the architecture does not serve.
Found in the first week, a contradiction is a conversation. Found in the last week, it is a rewrite.
I go into this in more depth in my book, The Solution Architect's Journey: Mastering RFP's through stories.