Jura has explained well, To 'look for' an object is to visually seek it out - 'He was looking for his glasses' It implies a simple expectation, the person is simply trying to find the glasses he has misplaced. To 'search for' is to seek out with a greater level of care, it suggests an investigation, - 'He was searching for his cat' it implies a certain level of difficulty in finding the lost item. If in doubt look at the word origins, Hope that helps! Clemency

They are similar in a broad sense. "Look for" is simply to try and find something. "Search for" is try and find something that is hard to find. You could misplace your sunglasses for example and be searching for them all over the house but you wouldn't use the word "search for" when you are referring to a car.