To shutter-speed: 1/focal_lenght is a good rule of thumb. At 300mm use 1/300 as the longest time. @Misha: Cable release is great if you can switch the mirror before shooting (dunno how you call that in english). With Cams as the Canon 300D or lots of cheaper analog SLRs (which do not have that option), using a cable release can even make things worse. I constantly find myself using the cable release and having the other hand on the cam when shooting. The more if you use a lens-collar.