meticulous \muh-TIK-yuh-luhs\ (adjective) - Extremely or excessively careful about details.

"But then, Eve reflected, from what she knew of Towers, the woman had been meticulous. In her dress, in her work, in maintaining her privacy." -- J.D. Robb, 'Glory in Death'

Meticulous ultimately derives from Latin meticulosus "fearful" (from metus, "fear"). The present sense stems from French méticuleux "overscrupulous." In present day English, the word usually carries a more positive connotation and is synonymous with precise and punctilious.