Fever is usually present with the flu in up to 80% of all flu cases.  A temperature of 100 F or higher for 3 to 4 days is associated with the flu

A hacking, productive (mucous producing) cough is often present with a cold

A non-productive (non-mucous producing) cough is usually present with the flu (sometimes referred to as dry cough) 

Slight body aches and pains can be part of a cold

Severe aches and pains are common with the flu

Stuffy nose is commonly present with a cold and typically resolves within a week

Stuffy nose is not commonly present with the flu

Chills are uncommon with a cold

60% of people who have the flu experience chills

Tiredness is fairly mild with a cold

Tiredness is moderate to severe with the flu

Sneezing is commonly present with a cold

Sneezing is not common with the flu

Sudden
Symptoms

Cold symptoms tend to develop over a few days

The flu has a rapid onset within 3-6 hours.  The flu hits hard and includes sudden symptoms like high fever, aches and pains

A headache is fairly uncommon with a cold

A headache is very common with the flu (80%)

Sore throat is commonly present with a cold

Sore throat is not commonly present with the flu

 Chest
Discomfort

Chest discomfort is mild to moderate with a cold

Chest discomfort is often severe with the flu