“You just need to get out there and talk to people more.”
Your male friend finds it hard to meet girls, and has asked for your advice on how to find a girlfriend. You think your friend is just too shy and needs to be more outgoing, so you say this.
You just need to get out there and talk to people more.
"You need to ___" is a really strong and direct way of giving someone advice or orders. It's usually used by parents, teachers, and bosses. It's usually used when they're angry or annoyed:
You need to stop talking and pay attention.
You need to get the account manager on the phone and tell him you're sorry, but you made a mistake.
The phrase "get out there" means to go outside of the places that you usually spend all your time, which for most people is just home and work, or home and school. "Out there" is wherever people are socializing and doing active things.
You use the phrase "get out there and ___" to advise someone to be active and energetic. For example:
If you're worried about the environment, don't just talk about it. Get out there and do something about it.
To be a good salesman, you have to get out there and talk to your customers.