I think it's still okay to use the word weblog on the Internet, so don't panic too much. But, yes, you're right, it can take a few months to really figure out how to move around in Movable Type and configure things "just so". I still tweak and fiddle with my MT weblogs, and one of them's two years old at this point!

Fortunately, there are some great tips that I've found that'll make working with MT a lot easier, at least for me. In no particular order:

• Click on the "New Entry" link to get to the Create New Entry page in Movable Type. Now bookmark that page. That's the page I have bookmarked, and when I think of a posting, I'm only one click away from being able to start typing away.
• The Create New Entry page can be customized, and you should do that, to remove ALL the clutter that you otherwise ignore anyway. Don't ever specify an "Excerpt"? You can remove that. Don't care about pings? Chop that baby out too. Just click on "Customize the display of this page" at the very bottom of the page, and you'll be amazed and what you can do to simplify the input area. (I still wish the text input boxes were bigger, though!)
• When you click "Edit Entries", try and learn to love "power-editing mode" (it's a text link in the intro paragraph. I have one Weblog where I sometimes post articles on behalf of other authors, and othertimes have articles queued for later release. Both of these can easily be changed en masse from the power editing screen. Well worth learning more about!
• Don't be afraid to fiddle with the date fields. Last I checked, there's no rule that says the date on a Weblog posting has to be exactly when you posted it. Worse, in MT the date tends to be when you first entered the article in the system, not at all the same thing (as I'll mention in a sec). Another great improvement to MT would be to have all the 'pending', 'draft', or 'future' articles in a different area than the published articles too...
• Which leads to another tip I've found: when you think of an article for your Weblog, or want to save a question someone's asked you, just cut and paste it into an MT entry and save it as a "draft" (rather than "publish") article. Then it's happily sitting in the queue (or, possibly, getting lost on the Edit Entries page because MT uses the date-first-entered which can be older than newer postings) ready for you to go back to it and add more thoughts, refine your discussion, add additional research, whatever. When it's "just so", then simply switch "draft" to "publish", make sure that the date is what you want, and "Save". Poof. It's published.
• As you're writing and editing your latest blog missive or screed, occasionally click on "Preview" to see if you're entering your tags properly (btw, see my article What are the essential HTML tags I need for Blogging?), then use "Re-Edit Entry" to jump back to your editing. To save what you've written, change Post Status to "Draft" and click "Save". Then go back and edit some more.
• If you have a weblog with categories -- and you probably should -- and you sometimes post entries to more than one category, remember that it's better to save your post as a Draft, then you'll see the "Assign Multiple Categories" text link under the Primary Category pop-up menu. Add the additional categories you want, then switch the Post Status to "publish" and you'll publish and ping the various blog tracking sites once, not twice.
• If your Web browser supports it -- and it should! -- I encourage you to have more than one window open with different Movable Type screens shown. For example, if I'm working on my templates, I'll have another window showing the actual page (or RDF/XML) that's produced by the page I'm on.
• Here's a huge timesaver that I only just recently learned: when you edit your template file and have to rebuild, never click on the "rebuild" text link on the top because it always defaults to "build everything" and offers few alternative choices. Instead, use the refresh button on the bottom of the screen and you'll find that -- magically -- MT knows exactly what file or files need to be rebuilt and only rebuilds those. A big time saver!!
• The Import/Export button offers you something that you might not even have been thinking you need: a way to back up your weblog. After all, your ISP might be one of the many lazy low-service sites that don't actually back up any of your files. Even if they do backups, every so often create your own (they're small, make two!) by clicking on "Import/Export", then scroll down to "Export Entries". You can read the small print, or you can just click on the text link at the bottom "Export Entries From [your blog name]" and save the resultant file.

Those are the top tips I can think of at this point. There are plenty more, esp. since I have posted over 500 weblog articles since I installed the latest version of Movable Type on my server! As I think of them, I'll add 'em as comments, and if you have any of your own favorites, heck, I'd love to learn about them, and I'm sure everyone else would too.