There are three main musical periods that are studied for OCR GCSE level; Baroque, Classical, Romantic and 20th century.
Baroque Music - 1600-1750
Composers include J.S. Bach, Handel and Purcell. ( think of Trees, Doors, and Washing Up Powder )
Usually remains the same throught the piece, with no accelerando (spead up) or ritardandi (slowing down)
The rhythmic pattern as remains the same throughout.
Phrases can be quite long and LOTS of ornaments such as trills and mordents are used.
May be Homophonic or Contrapuntal but usually they are Polyphonic, what is polyphony I hear you ask? its simple really: two or more parts playing different parts, at the same time.
Now its all well and good me telling you all of these features however yiu really need to know how to spot whether a piece of music is from the Baroque period. so how do we do that?
First you listen out for a Harpsichord (an early type of piano played by strings being pluscked rather than hammered like nowadays) this was in almost every Baroque piece.
Secondly you listen for the great use of trills. if you have both of these its almost certainly Baroque.
However, if you just want to make sure you're right, look out for polyphony. Yes, it really is that simple.
Classical Music - 1750 - 1820
Composers include Mozart and Haydn, unfortunately i dont have a cool way of remembering these ones but…