Let’s say you’re gunning for the keyword: “red shoes”. You COULD simply optimize your title tag around the keyword “red shoes”.
But it’s smarter to embed a long tail keyword into your title tag.
(For example, you could optimize your title tag around “best red shoes” or “cheap red shoes”).
That way, you can quickly rank for the long tail keyword “best red shoes”. And over time you can ALSO rank for your main target keyword, “red shoes”.