In practice it's about bribing them or at least telling them personal gains. Like if you tell a politician he should support the war on Iran because he owns lots of oil stocks and they'll go up.

Marketing is telling a politician this app is the future of EU social chat so you need to be using it.

You would have to be exceptionally naïve to think that a good chunk of the "lobbying" done doesn't involve some sort of exchange of something of value.