You can even go one step further and just trade on platforms that have a live demo feature, there's plenty of them available—even for spot exchanges, derivatives and margin trading platforms.

Alternatively, you can just plot your entry and exit points using a technical analysis and charting tool like Teamviewer, most of the exchanges have integrated this anyway.

Just google "cryptocurrency exchange demo trading" and you'll find a bunch of platforms.

Be careful though, most platforms only give you a fixed amount of testnet funds to play with. After that you'll need to either recharge it move to the main trading platform.