Identifying this card involves recognizing its unique artwork and the set symbol
However, if you own a copy that is less than perfect there is a huge price drop off, with NM 7 Mewtwo (Holo) valued at around 390
On one hand, the Pokemon TCG has remained successful globally since all the way back in 1996, and for newcomers to Pokemon cards, its a great way to learn about card collecting and even playing the game (though there are some differences in both regards)
Older cards don't have a set code so, you need to know the symbol for each set to be able to tell on-sight, but a quick search over on Gatherer can help you out when youre not sure
First, keep it simple by selecting a straightforward strategy that allows you to grasp the game mechanics more easily
I usually store mine in a binder for trading, but its more difficult to trade during these times