rule of thumb: take off distance and weight

I read in mag article regarding a "rule of thumb" for calculating take
off distance required when weight increased, but I cannot remember what
is it. Does anyone know?

Also, are there any "rule of thumb" for calculating take off distance
per power loss, or increase elevation? How about power loss per 1000
ft increase in elevation?

Is there a source for all kind of flying "rules of thumb?"

Thanks.