Say someone sends you an email asking about your services. What's the next thing you would do? You want each pipeline stage to reflect in past tense what has already occurred in that stage (not what needs to be done).
Stage 1: Call Booked
Say that the first thing you would do is respond to the inquiry and ask the prospective client to schedule a meeting. Once the meeting is locked in, you can convert the lead into an opportunity and they would sit under the first column named Call Booked.
Stage 2: Second Meeting Booked (Or "Call Completed")
What happens once you've completed the initial call in stage 1? For this example, say at the end of your first call you invite the prospect to a second meeting that is longer in duration. Therefore, you would name your second stage "Second Meeting Booked".
Stage 3: Proposal Sent
After the second meeting is booked, what happens next? Let's say you send them a quote with a proposal, therefore naming the third stage "Proposal Sent".
Stage 4: Proposal Signed / Payment Received (Client Won)
So now that you've sent them proposal, say they become a client. Now what? You'd likely mark them as a won client! What's the first thing you normally do after a prospect becomes a client?