carefulAfter careful consideration, we are unable to accept your proposal.
thoroughHe seems like he's not paying attention, but don't be fooled - he's very thorough.
meticulousapprovingThis book is the result of years of meticulous research.
methodicalI appreciated his methodical approach to the work.
painstakingShe's documented everything in painstaking detail.
rigorousapprovingTheir rigorous approach to the subject earned him them respect of their colleagues.
preciseapprovingAs a dancer, he's very precise.
assiduousformalWe have been assiduous in trying to address the problem.