@DaanSander Read the thread is all I can say, most of them will say "download blah" or "copy this class" etc. If there is a thread with no download and no code to copy then maybe the thread owner has forgot to put it. In most cases it is classes and downloads, just read and see what it says. If it is using the methods, check if there is a JavaDoc and/or a explanation if not then ask the author to maybe put an explanation or a JavaDoc up.
http://bukkit.org/threads/effectlib-manage-your-effects-the-nice-way-text-image-in-particles.259879/ i have read it but when i try it it still does not work i added the jar to my library
@DaanSander Could this problem of yours have any relation to this? http://bukkit.org/threads/using-another-jar.345092/