You forgot that all quotes must contain a 6 in themAh, markups.
You have come to the right place.
Now read carefully
Markup plan #1: Take everything you know and multiply it by a good number. I like to use even numbers.
Markup plan #2: Materials X 3 plus something for momma.
Markup plan #3: Take a good guess and hope your close.
Markup plan #4: Buy some books about running a construction company, this takes the longest to learn, and its what the pros do, but no instant answers which is what you really want, isn't it?