Hi there,

Adi has given a great answer.

Let me just boil it down a bit more simply to make it all more memorable!

"Talk softly and carry a big stick" - Teddy Roosevelt

1. Start with empathy. When you first meet any client, get to know them. Ask about them, hear about their lives/days if that's what they want to talk about or their complaints/gripes if that's what they want to talk about. Show them you're just like them
2. Be as unobstrusive as possible - Make your request very clear, very simple, and do as much for them​ as possible to make their job easier (i.e. setup the excel columns for them). Secondly, be darn sure exactly what you need from them when you ask. .The worst thing you can do is get them to spend a bunch of time for you, only to then tell them you need it done differently, or you missed something, or need something else. You need minimal "asks"
3. Bring "color" to your request - asking in person is always best. Starting off the conversation with small-talk is generally best (if they're that type of person). When asking, try and show them why it's important and how they'll be recognized for helping you.

^If the above steps fail, escalate early and often to your manager. They will know whether the individual's boss needs to be contacted to put some urgency to the matter :)

(edited)

Ask nicely and with empathy. If that doesn't work escalate quickly. Delayed data can derail the entire project, so critical to get this in place quickly.

Hi, cooperative persuasion is an important skill to develop, sometimes assessed during the Personal Experience Interview. The first step is aligning the client with the overall goal of the CEO, while showing how important would be also for her team the achievement. If it does not work you can make an escalation to the management.

Best,
Antonello

+1 Adi and lol Ian! ;)