  We present our ground-based CCD observations of the close binary systems DD
Mon and XY UMa in B, V, R and I bands. The light curves are analyzed using the
Wilson-Devinney code (W-D) for the derivation of the geometric and photometric
elements of the systems. We compare the methods of photometric and
spectroscopic mass ratio determination in these binaries, as a function of all
typical difficulties, which arise during the analysis of such systems (light
curve asymmetries, third light etc). Finally, a new spot model is suggested for
the eclipsing system XY UMa, which belongs to the RS CVn type of active
binaries.
