Though I play electric bass exclusively, my main instrument for almost 50 years was classical guitar, so everything I played was read first from notation. Someone earlier evoked Louis Bellson's book, for which I concur, all musicians should use. As when I studied it, I simply clapped my hands along with a metronome, it has become my habit to read through the rhythmic component of new material especially jazz whose rhythms, to me anyway, are still far from commonplace. After a mental read through I'll have a go at sight reading it. As with all study, breaking something down into simpler components makes it often doable. Soon, as was also mentioned familiar rhythmic forms show up in new material and your reading should progress.
