This thesis presents a comprehensive study of magnetic cataclysmic variables to map complex accretion flows, dynamic state transitions, and the secular evolution of intermediate polars, using ground-based and space-based observations. We refined the fundamental periods of the intermediate polar V709 Cas, identifying a primary disc-overflow state interspersed with stream-fed accretion along with two-pole accretion signatures. Among four intermediate polar-like systems analysed, we detected gradual orbital decay in V1460 Her and reported the first detection of beat period for 1RXS J045707.4+452751, indicating a disc-overflow geometry. Crucially, our temporal analysis places the intermediate polar V515 And in the 2-3 hr period gap. This system also exhibits a transition between disc- and stream-dominated accretion modes, displays consecutive outbursts indicative of the micronovae phenomenon, and shows an inverse Balmer decrement, corroborating its magnetic nature. Finally, a study of eight candidate magnetic cataclysmic variables yielded a range of orbital, spin, and superhump periods. Optical spectra confirm that the sources CRTS J032034.5+203607 and CRTS J021633.89+251346.5 are magnetic systems, while classifying two others, namely LAMOST J071553.88+581606.4 and RX J0153.3+7446, as definitively non-magnetic. These results deepen our understanding of accretion mechanics, outburst triggers, and the evolutionary pathways of highly magnetised interacting cataclysmic variable systems.