To avoid making costly mistakes, you can conder,
Keeping separate funds for expenses and emergencies
Seeking financial advice from those who have been in bitcoin investments for long. Making informed investment decisions
Even though everyone must make their own decisions, but being informed and patient can help you succeed in the long run.
I also have a different suggestion to make on this, if you think you have money assigned for a bitcoin investment and would appreciate touching over it, then try to distance yourself far away from where you could get hold of the money or even the bitcoin after investing, one can make use of a time lock to avoid getting in touch with it, also, it can be secured on a cold storage and then we device for a means to securely save the private keys.