1. Show up on time.
When you show up late, several things happen:

Office staff have to scramble to reschedule all subsequent calls.
Lose calls because you're running out of working hours.
Client starts to doubt the company.
Client becomes angry.

Your client's time is valuable.  More valuable than your own, in fact.  Anywhere up to 5 minutes late is acceptable, but it's always better to be either early, or right on time.

Imagine showing up a half-hour late to a job.  The client is standing at the door, arms crossed, and short-tempered.  Already upset about having to call in a service professional, the client may also be taking time off of work to meet with you.  As a result, she's now a half-hour behind where she wanted to be.

At this point, you're facing an uphill challenge to provide service to that client.

If you have to show up late, make sure that you're still early.

Programming the address into your gps device, you can see exactly what time you're going to be arriving.  Call your dispatch center with the eta given, only add 10 or 15 minutes.  They will call the client with the eta, and then voila!  You're earlier than they said.

The client is happy that you're early, and a barrier towards a sale has been removed.

2. Stay inside the house.
Before you head inside, make sure that you have all of your pen, calculator, writing pad, diagnostic tools, booties, and gloves with you.  If there's any reason at all for you to go outside, it gives the client a chance to think about what's already been said, and call your dispatch center to cancel the call.

A good strategy to avoid this is to always leave something behind.  If you're getting close to an agreement with the client, excuse yourself by offering them a few minutes to think things over while you go to check on the material in your truck for completing the job.  Leave the paperwork sitting out in the open, and head outside to collect whatever it is that you're missing.

This isn't going to stop people from putting your stuff out on the front porch, but increases your chances of staying on the job site.

3. Plumbing checkup.
The key to more sales is to find more things to fix.  Before you've even thought about bringing out your price guide, you should get a feel for the current plumbing setup.  The plumbing checkup will help to build value in the client's eyes.

You don't want to just start walking through your house like you own the place.  Make sure you confirm that you can fix the problem that you were called out for, then ask the client if it's okay for you to take a look at the rest of the plumbing.  "Mary, now that I've seen the problem, and have determined I'll be able to fix it today, would it be alright if I looked at the rest of the plumbing to make sure that this is an isolated problem?"

Most of the time they'll say yes.  But if not, that's okay too.  You can always do a checkup further on during the appointment.

The purpose of the checkup is to find any glaring deficiencies which the client may not realize is a problem.  At the same time, it gives the client a chance to remember any leaky faucets or other minor problems.

4. Customer service plan.
This is an opportunity for the client to save some money.  The sooner you can get the client thinking about this option, the more time they'll have to convince themselves to be involved with it.

After you've done your plumbing checkup, and you can show how much they'll be saving in various repairs around their house, the more apt they are to invest.  There will also reach a point where the savings will outweigh the investment of the service plan.

5. Ask for a referral letter.
The best referral letters are from customers who purchased, but there's nothing wrong with asking those who didn't.  If you've been honest and straight forward with your client, and they are generally pleased with their service call, it shouldn't be a problem obtaining the letter.

Offer your client a $25 discount on their invoice if they write one on the spot, while you're finishing up your own paperwork.  You would preferably want it written on their own letterhead, but if that option is unavailable, having it written in their own hand on the writing pad you brought in is just as good.

Whenever you get a referral letter, you want to place it in your presentation binder.  Either laminated, or in sheet protectors.  These referral letters will help in future sales, as potential prospects will see an ongoing history of satisfied clients.