How to stay safe when browse the deep/dark web?

Tor hidden services are no more unsafe than the regular Internet.So don't Scared to much,The key part of "Dark Web" is web. The same best practices you should apply anywhere else on the web will help keep you out of trouble on the "Dark" web. 

1. In fact, you might even be safer on the Dark Web if you play your cards right. If you're using the Tor browser bundle, it comes preconfigured to protect you against some of the privacy threats that normal browser configurations would subject you to.
2. This should go without saying, but it's surprising how often it comes up: If you register on a hidden service site, don't use your real email address. Create a throwaway email. And don't use a username - for the email address or anything else - that you've used before or plan to use elsewhere. And most certainly don't use your real name.
3. If you engage in a commercial transaction, use a site that has a good reputation. Never pay with a credit card - there's little recourse in tracking down a hidden service operator, and a chargeback might be awkward to explain depending on your transaction. If you pay in Bitcoin, use a site which provides an escrowservice.
4. If you absolutely must download something (and I wouldn't suggest it if you don't know what you're doing), scan at VirusTotal or a similar service.
5. If you live somewhere connecting to Tor might cause problems for you, consider connecting to Tor via a "bridge". This isn't foolproof, but it will make it less obvious that you're connecting to the Tor network. You can find instructions for getting bridge addresses and configuring your software at Tor Project: Bridges.

When using Tor, be aware that when browsing the normal web, the operator of the exit node (the server in the chain closest to the site you're accessing) can see your traffic if it's not encrypted. Be mindful of using sites that don't support encryption if you're submitting personally identifiable information.

With the use of Tails, a Linux distribution that can be booted from a USB stick, and automatically routes all traffic through Tor. One of its benefits is that even if something goes terribly wrong, you just have to reboot (or in a worst-case scenario, reformat the USB stick) and everything is back to normal - you can browse with minimal risk.
  
Tor and its hidden services are a great resource to explore, and learning to navigate them is a keen way to build your skills for day-to-day web use - after all, if you can make it there, you can make it anywhere