In my opinion, patience is the most fundamental thing which you need to have in yourself if you are planning for long term investment of money. If you are bad in controlling your emotions, then there are likely chances that you will not be able to hold your coins for much longer and you will simply sell your coins at the time when the market value will be falling. Getting panic is the worst thing which you can do.
Here you also need to add that investing in something can only be the amount of money that you are ready to lose. After all, many people start to panic because they invest too much money that they cannot afford to lose.