A turning point for my agency was when we introduced a project workshop for all new projects. But before I get into that, let me tell you about the good old days...
In the early years I would do anything to impress a potential new client, I was very confident that technically we could hit their project out of the park - we just had to first navigate through this awkward sales dance first.
Back then I think my dance was pretty stock standard for a developer turned agency owner, I'd woo the client with examples of fantastic work we had done before, I would enlighten them to how cutting edge we were with our technology stack - and I'd ask lots of questions about the problems they needed help with.
Hopefully they had some type of written specification (or written anything!) that I could then reference when putting together a time and cost estimate for them (I mean let's be honest, that's why they were here), and then I would send it off to them along with a proposal basically saying "I love you, we can be fantastic together, please choose me".
I wasted a lot of time approaching sales like that.