It’s that time of the year again. If you are an executive director or part of your nonprofit organization’s fundraising staff, you and your peers are getting ready to send out the end-of-the-year fundraising appeal. As with anything we do repeatedly, it is easy to slip into bad habits. And without even knowing it, some practices can erode your bottom line.

To help you do a quick self-evaluation, I’ve described below five common bad habits that can make your appeals less effective—and donors less likely to give. If you catch yourself doing even one of them and make some smart adjustments, you may end up enjoying an especially happy holiday fundraising season.

1. Sending everyone the same message

Do you really want to send the same message to people who have already donated this year and to people who have never given? Not acknowledging a previous supporter’s donation is like greeting a good friend at a party by extending your hand and saying, “Hi, it’s nice to meet you.” With all of the database technology at hand, every organization should be customizing their appeals. Here are some tips on segmenting your database for the end of year letter (and discovering the joys of terms like “LYBUNT” and “SYBUNT”).

2. Overreliance on emotional stories

I am a big believer in the power of stories to appeal to prospective donors. But end of the year letters that contain only stories and little data demonstrating overall impact make me suspicious. This major study on donor attitudes shows that I’m not alone. Don’t forget to compile your stats, display them in a compelling way, and persuade people like us. Here are some examples of nonprofits that borrowed corporate formats to convey their impact.

3. Killing with words, words, words

In our communication era, people have a decreasing capacity to consume long stretches of text. During the holiday season, as more and more physical and electronic letters arrive than usual, that capacity plummets even further. Nonprofits would be well advised to look for other media to embed in their annual appeals. Here are some tips on using videos to boost year-end donations. This is an excellent article from Social Brite that illustrates ways to use photos and other imagery to tell your story.

4. Neglecting the little things

Almost a quarter of all email opens occur within the first hour of being sent. This means that a little thing like when you’ve scheduled delivery of your electronic appeal can make a real difference (read more on the issue of timing in email marketing). Your placement—and testing—of your hyperlinks to a giving opportunity can also have outsized impact. For physical mailings, the biggest little thing you can do is to include a handwritten message: Some studies show that this increases the chances of a donation by 300 percent.

5. Botching the thank you

One very obvious bad habit is to forget to send a timely thank you to donors. According to Ahern Communications, one large agency tested the importance of thank you cards by sending them to one set of 25,000 donors and not sending them to another set of 25,000 donors. The result a year later? The two sets gave similar numbers of gifts but the amount of donations from the group that received thank you cards totaled $450,000 more. Thank you cards matter—but beware: According to other studies, thank you gifts can backfire psychologically by ruining the donor’s sense of altruism.

I hope these suggestions help your fundraising this holiday season. Best wishes on your efforts, and thank you for all you’ve done for the sector this past year.

Read more stories by Curtis Chang.