If you're trying to download new releases or really popular files, you might be seeing fakes. Typically, these have lots of sources (up to 100) but won't ever download... sit 'connecting' & then go straight to 'need more sources'.
Search again. Vary your search terms (look for artist, album, actors' names etc) & stay away from files with huge numbers of sources. I go for files with 10 sources or less.

If you're searching for video, look up the file before download with Bitzi. If the file's been rated then you'll get an idea of content & quality. A file with many sources but no Bitzi rating is often a fake.
How to use Bitzi