Read the volume notation and play as written. Volume dynamics include the letters mf for mezzo forte, which means to play the indicated music medium loud. The f means to play the indicated music loud. The letters ff indicate very loud. The letters mp tell you to play a piece medium quiet, a p means quiet and pp means very quiet.
Read the gradual dynamics and play them as indicated by the markings in Step 1, but apply these dynamic markings gradually rather than immediately. For example, mf followed by a gradual marking would tell you to gradually build to a medium loud volume. These markings typically appear beneath the music staff. A p followed by a line indicates a gradual softening of a piece of music. The abbreviations "cresc" and "decresc" mean crescendo and decrescendo, or gradually louder and gradually softer. A p or f followed by a long caret shape indicates slowly lowering or increasing volume, depending upon which way the caret goes. If it starts small, you'll start quiet and rise in volume.
Interpret accent dynamics depending upon the instrument. A small caret placed above a note or series of notes indicates playing the note harder or with a staccato feel. You may see an sfz or fp marking with these caret accents, indicating the accents should be played with volume or force. The sfz means to play a note, then back away from the note and play it again.
Play a passage smoothly when you come across the word "legato" written beneath a passage. The abbreviation "tr" means to play a trill. "Poco" means gradual and is often used in conjunction with other dynamic markings. The abbreviations "dim" (gradual reduction) or "accel" are often used in conjunction with other markings as well.