Write the will.
The will must be written entirely in your handwriting. It may not be typed.
Indicate in the document that it's a will.
The will should indicate that it is your intention that this document is your last will and testament.
Date the document.
It is good practice to put the date on the will.
Sign the document.
The document must be signed by you in your handwriting.
Store the document properly.
The will must be stored with your other valuable papers and personal items when it is found after you pass or it will not be considered valid.
One misstep and holographic wills don't work. I would recommend that you go to an attorney and have the will done professionally.