bro,
well i wouldnt say that im good at this
pero its all a matter of practicing talaga.
at first, yeah, i was losing count, or losing tone on my voice
pero practicing a lot really helps
a good example of this is Paramita's Drummer/Vocalist
at ang mahirap pa sa kanya, hindi basta basta yung beat niya
and also, as duyduy said, feel the song muna
so that the groove is already in your head
ayun
hope this helps