3) Hide 'last seen' timestamp
Not sure you want people to know when you're coming on and offline? You can disable or restrict who sees your 'last seen' time in WhatsApp's 'Profile'; 'Privacy' menu, in Android, iOS, Windows or Blackberry. Be aware though, if you turn it off, you won't be able to see other users' 'last seen' times either.
4) Restrict access to profile picture
If anyone download your pic from your WhatsApp profile and, using Google Image search, very quickly find out more about you. Set profile picture sharing to "contacts only" in the Privacy menu.
5) Watch out for scams
WhatsApp itself will never contact you through the app. Also, WhatsApp does not send emails about chats, voice messages, payment, changes, photos, or videos, unless you email their help and support to begin with. Anything offering a free subscription, claiming to be from WhatsApp or encouraging you to follow links in order to safeguard your account is definitely a scam and not to be trusted.
6) Deactivate WhatsApp if you lose your phone
WhatsApp offers users simple and effective security tips to keep control of your account if your phone is lost or stolen. As well as locking your SIM card through your network provider, WhatsApp recommends that you immediately activate WhatsApp with the same phone number on a different phone, with a replacement SIM. The app can only be used by one number on one device at a time, so by doing so you instantly block it from being used on your old phone. If that's not possible, WhatsApp can deactivate your account.
7) Be careful what you talk about
Last but not least, use the same common sense you would with any form of digital communication. Don't send personal information if you can possibly avoid it - addresses, phone numbers, email addresses - and never send your bank, social security or credit card details, or your passport or other identification details.
8) Remember to log out of WhatsApp Web
WhatsApp recently made a lot of noise with the launch of WhatsApp Web. The mirroring service makes life easier while working on PC. However, most users are unware that they should ideally log out of WhatsApp Web on Google Chrome browser either from their mobile or the browser.