The investment strategy is as we all know - HODL
The best way to trade is - Buy once a DIP happens and sell once the market is BALLOONED/HYPED up more than it should. This is probably the best thing you can do or just go with altcoins and buy potential gems but they are hard to find in coal(scam coins) all around.
There are so many different investment strategies and however the most important investment is that in the long term of course the best word is HOLD, if it is not strong after looking at the market then you don't have to go at a time like and it's better to trade when the bull run occurs.