No matter how many mistakes you make or how slow you progress, you're still way ahead of anyone who isn't trying.

Very few marketers even make the effort of doing Thank You cards. Should this be part of your everyday routine? Are there tasks that are a "better" use of your time?

Maybe. But, what if, no matter what niche you're in, you just singled out 4 random customers today and just jotted down 4 quick Thank You's? It would take just a few minutes out of your day but put you way ahead of the curve.

You just want to thank your customers for buying from you. There's no "sell", no discount and no hustle. You are just thanking them for their business. They are part of your success. Here are your tools for "Thank You" productivity...
Thank-You Tool #1: WPKunaki
On Robert and Lance's website, MembershipCube.com, as well as their other membership sites, they use a plug-in called WPKunaki, which is an address collector.

When someone joins their membership site, the plug-in pops up and asks for their mailing address and runs it through the address validator. Lance would be really crazy not to be collecting addresses.

It's nice to have it on hand. He can use it for Thank You cards, he can use it to send them webinar or DVD copies as just a quick bonus. He can also use it for geographics to target customers later for Facebook ads.
Thank-You Tool #2: Phone Calls
Sometimes Lance will even call them on the phone.

If someone just bought a $7 e-book from you, they're not expecting anything at all, not even an auto-responder-generated email. So, if you make that call, you're way ahead of anyone else.

If someone bought from you and you contact them the same day, they are going to just be happy and not have any complaints.
Thank-You Tool #3: Send Out Cards
This is a service that will allow you to send traditional cards to your customers. These are NOT electronic cards. They are "paper" cards like you would get at the store so they are very personal, not "mass e-mailed" and they won't go to your customer's spam folder or look like another sales push.

There are also gift options within the Send Out Cards system that you can send to your customer as well.

To learn more about how Send Out Cards can help you personalize your relationships with your customers, go to DoubleAgentCards.com.
Thank-You Tool #4: Google Drive
If you have a Gmail account, you also have a drive account. If you don't already have one, go get one. It's free.

You can create any doc and have it be in your Google Drive, where you can now access it from anywhere.

A good idea here is to keep a journal of different contacts/activities that have with your customers. Here is where you can keep a journal of the Thank You cards that you send out.
"Cheesy" Marketing
You want to stay away from cheesy marketing. Many marketers tell you to look up today's holiday and give your customers a "special discount" for that day (example: a "Boxing Day" discount) or to look up your customers' birthdays market to them on their birthdays.

It sounds like a good idea but all these marketers who teach this have never personally marketed to me on in this way. They've really just posted an occasional sale here and there when they're probably running low in their bank account.

It makes more sense to just sell what you sell and be consistent. You don't have to have sales all the time if you're thanking your customers for being there.
The 1-4-15-80 Rule
This is an important concept that Robert talks about in his program Double Agent Marketing and its accompanying book. It's how your list is broken down:

About 1% will buy everything you put out.
4% will buy most of your stuff.
15% won't always buy high-ticket items but they will probably buy things where they can do a payment plan.
Then, your last 80% will probably not buy anything products/services over $20.

If that disappoints you, you can build a bigger list OR you can take better care of your list.