At a very basic level both the title tag and meta description tag should have your target keyword(s) in them. Although you don’t want to over do this, placing the keyword once (maybe twice) in each tag is plenty. Think of the title tag like your name, it’s succinct and identifies you. The meta description tag is like a mini-bio, quickly describing who you are.
Every webpage on your website has both tags, and it’s important that you fill out each for search engine optimization purposes. If you have a CMS like WordPress then this becomes very easy, but having to dig around in the HTML can be tedious, so if you are not on some type of CMS check into transitioning over to one.
The meta description tag should provide a short description of the web page, keep it under 150 characters – usually 2-3 sentences is good enough. Think of the meta description tag as your sales copy, persuade the user to click on your website link when they find it in Google.
The title tag is extremely important to your overall on-page SEO, and is something the search engines place a lot of value in. So make sure you have the appropriate keywords in the title tag, and keep it at 70 characters or less.