*Typical baroque music features, lots of frilly ornaments and fancy bits such a trills & turns.* Look at the instruments, your most likely to hear string instruments, wind instruments. The music is often accompanied by the basso continuo. It is usually accompanied in chords and features keyboard instruments (harpsichord http://wiki.answers.com/Q/What_instrument_would_most_likely_play_the_basso_continuo_in_a_Baroque_musical_piece#, organ family) and early guitars (lutes, theorbos, gitterns). The work of the chording instrument can be supplemented by other lower register instruments: cello, viola da gamba, bassoon family members. In most cases of Baroque composition the makeup of the basso continuo group would be left to the performers (and the part itself would be largely improvised).
* It is normally whats called homophonic which means melody and accompaniment, so the lower register and the basso continuo play the accompaniment, accompanying the higher instuments which chords.* There are no pianos, trumpets, clarinets and other modern instruments