Pay attention to online discussions on reddit and other forums. What stocks are being discussed. Enter early with small bets on several of these and wait. Just like fishing with several rods. When any of them take off ... don't get greedy or stay too long on it. Sell and be happy with the gains you made. Repeat.
Obviously the current stock price of GameStop is not really a reflection of the actual company value (i.e. in terms of its ability to return / generate money as an entity). When this unnatural social media astroturfing is fading the stock will fall as quickly and as hard as it did rise. If you have the guts (it is not at all without risks (well nothing is when trading)) you could chose to short it now.
Continuously check out what is being said about GameStop on /r/wallstreetbets. Find clues on what direction the mass is moving: Selling och Buying? Act cleaver and quickly on those signals. Train your ability to see what is real call for action and what is just noice. You will get better over time.
Whenever a stock is rising or falling at extreme speed there is always a tendency that the market is overreacting. The stock price is moving with the momentum of a rolling snowball almost. When the movement seems to start slowing down it is quite common to see a short counter reaction ... kind of a recoil. Look for the slowing down ... the levelling out ... and invest on a recoil movement. Expect it to be kind of short. Get in, make profit, get out.
Of course there are no guarantees there will be a recoil. Well there never is any guarantees when investing in stock. But quite often this happen and can be exploited if you get an eye for it.