• Superlatives of superiority
• If the adjective is short (monosyllabic):
Willy is the tallest guy in the building. Willy is taller than everyone else in the building.
My boss is the craziest person I have ever known. I have never known anyone crazier than my boss.
Note: There is no strict rule to determine if an adjective is 'short' or 'long'. Obviously, monosyllabic adjectives are considered short, however there are some two-syllable adjectives which can be both short and long:
happy -> happiest or most happy
ugly -> ugliest or most ugly
• Superlatives of inferiority, with LEAST:
August is the least profitable month for sales. Less money is generated by sales in August than in any other month.
Of the three major cosmetics corporations, Grevelon generated the least revenue for the year of 2008. Grevelon generated less money than the other two major cosmetics corporations in 2008.
Last but not least... Importantly, despite being mentioned after everything else...
• Some commonly-used irregular adjectives:
good -> best
He's the best cook in town.
He cooks better food than everyone else in this town.
bad -> worst
What's the worst thing that could happen?
far -> farthest (literal distance) or furthest (literal or figurative distance)
The farthest south I have traveled in France is to Montpellier. Montpellier is the most southern point in France that I have traveled to.
Her birthday is the furthest thing from my mind. The last thing I am going to think about is her birthday.