If you're logged in, you'll see a Control Panel button near the top of your SmugMug homepage.

Click it and the first thing you'll see is:

Your Control Panel is for your eyes only. No one else can see it unless they log in as you. If you are a power or standard user, you'll see five tabs. Professional users see a sixth tab, "Pros".
Each tab holds useful stuff:
News
Shown above, this tab includes SmugMail, where you'll receive messages about new features, scheduled maintenance, and other important updates from the SmugMug crew. SmugNews is updated frequently and gives you the highlights from the latest Release Notes. The ClubSmug section keeps you current on discounts you receive as a Smugger.
Stats
Your Stats tab is the place to moderate and delete comments. Click on the # of comments to get more details and enable/disable comment approval. Comment help.
If you use the email sharing feature, all invitations to view your photos that you've sent are tracked here.
Your uploads are also tracked here. Click view log to review the last month of photos you've added along with any upload errors.
Photo views are reported and the more details link will give you the nitty gritty hits on each image size in each gallery. Tell me more.
Referred anyone? You'll see your referral credits rack up here. Click referral details and see the breakdown. What's a referral?
Settings
This is the place. You can change and update your billing information, SmugMug nickname, account level, and SmugIslands settings. You can also create or visit your SmugVault here.
If you want to add photos via email, create a photo email password here as well. You'll want the change link next to the word "passwords".
If you're a Professional or Power subscriber, you can also add a domain but make sure you've set up the domain properly, first.
If you're a Professional subscriber, you can change your guest password in this tab as well.
Pros
If you have a Professional SmugMug account and you've set custom prices, we'll track print orders where you made a profit. Click sales details to see a breakdown of every item on every order.
View and edit your custom watermarks. Watermark help.
View and edit your site-wide backprinting setting. Backprinting help.
Your customers see your email address when they place a print order. If you'd like them to see an email address that's different than the email address on your SmugMug account, add a customer contact email here.
Customize
View, re-name, or delete custom categories and subcategories. Help.
Create, view, edit, or delete sharegroups. What's a sharegroup?
Choose a default theme for your SmugMug pages. Theme help.
If you're a Power or Pro SmugMugger, you'll also see a
Customize link and a
Themes link. These are your ticket to changing SmugMug's look and feel, adding a custom banner to your site, etc.
Customize help.
Homepage
You can show up to 9 sections of goodies on your SmugMug homepage. Any you choose to hide instead will live in this tab. Click show to send a section to your SmugMug homepage where it can be admired by your visitors.