Just use following script as below
<meta name="keywords" content="<mt:EntryTags glue=", "><$mt:TagName$></mt:EntryTags>" /> <meta name="description" content="<$MTEntryBody words="30"$>" />
Please be carefully when you change your template file.
Follow me.
Login your Movabletype 4
Desing > Templates
Open Entry Template
Find
<title><$mt:EntryTitle encode_html="1"$> - <$mt:BlogName encode_html="1"$></title>
Add the code after it.
Rebuild your entry archives.
Done.
It is one of the most basic Search Engine Optimize methods. It make your entry page more Search Engine friendly.
You can put the code of my post right before
The reason why you can not found the title is different template. Your template may different.
Put it in header is OK, but do not cache it. Other wise all pages will have same meta.