I often find when Geocaching ordinary pencils don't seem to leave much of a mark at all, especially if the log is wet, and especially on the smaller logs pens are difficult to "get going" without a firm surface. Is there a better alternative I can use?
I often find a "soft" pencil, say 2B does the job much better than HB. Don't go too soft because then it'll be easy to turn into a smudgy mess, but as a general rule I find a pencil a bit softer than the norm works rather well.
Alternatively, if you prefer pen then breathing on a Biro to warm it before writing can often help get it going much more easily, especially in cooler weather.