1) Sell to people who can write the check, and have a budget to spend
That's my entire advice. It seems obvious. If you're selling to an individual, choose a demographic with money to spend. And charge a price to fit into their budget.
If you're selling to a team, don't. Sell to the person buying products/tools for the team, the one with signing authority. They make the ultimate decision. And they have a budget to spend, and will likely spend it all on something.
> market is the most important factor in a startup's success or failure.
If you get a bad answer to any of these, you need to do some thinking and talk with more/different users, and if no change then you probably can't make a business on this (and don't need to continue along the chain until then). Once those are true, then yes, sell to the people who can write a check.
While buying decisions are made on top, initial usage/trial decisions are often made by expert team members. I'll say, first soft-sell and get expert team members to try out your product, and soon-after ask them to connect you to the manager or decision-maker for further discussion.