How to lock your account on twitter so people have to request you?

[shelbsss]

I've looked everywhere for this in 'Settings' I dont like randoms following me.

[Colman]

Visit http://twitter.com/account/settings and select "Protect My Updates" at the bottom of the page. Once you hit save, you're good to go.

[David Smith]

Go to your account settings by clicking on the person icon at the top right of the page and selecting Settings from the drop-down menu.

Scroll down to the Tweet privacy section and check the box next to Protect my tweets (shown below).
Click the blue Save button at the bottom of the page. You will be prompted to enter your password to confirm the change.