Accents look similar to a very small decrescendo marking, and they can occur above or below a notehead, as shown below. Scroll down for sample practice exercises from lesson 7 of the Time Expressions book.
The accent marking indicates that a note should be given emphasis. We usually accomplish that effect on wind and brass instruments by pushing more air through the instrument at the beginning of accented notes. Therefore, even though the accent is an articulation marking, it can have a slight effect on dynamics, too. Similar to staccato notes, accented notes can be interpreted in different ways, depending on the style of music.
In these exercises, the notes without accents should be played with a smooth and connected articulation (legato) to create a contrast with the accented notes. To get the accent exercises, melodies, and duets written for your specific instrument, you can purchase the Time Expressions book. You can also get a free sample of Lesson 1 of the book.