How do I center my ads?

To center your ads, you can use the following CSS:

.adplugg-tag img {
    margin: 0 auto 1em auto;
}

If you aren't familiar with css, this says to put a 1 character bottom margin and automatically calculate an even (centered) left and right margin on each of your ads.  You can change the 1em to 2em for more space or 0.5em etc. for less.

For it to work, you add the above CSS to your site's stylesheet. If you are using WordPress, you can do the following to modify your stylesheet:

1. Log in to your WordPress administrator.
2. Go to Appearance, then Customize, then Additional CSS.
3. Add the CSS code from above.
4. Press the Save & Publish button at the top of the screen.

EDIT 2015-12-02: We have also had success with certain themes using this css:

.adplugg-ad {
    display: table;
    margin: 0 auto 1em auto;
}

EDIT 2016-03-24: We have also had success with certain themes using this very simple css:

.adplugg-tag { 
    text-align: center;
}