1. Use metamask extension or a hardware wallet;
2. Never enter your private keys on the website itself;
3. Make a bookmark of https://www.myetherwallet.com
4. Print out your keys and seed and keep them in a safe place; make a backup of your keys on a USB-drive.
5. Never open e-mails from unknown authors having suspicious links.

At least these precautions should be enough to protect your funds.