Find a Compression Program
There many programs available which enable .pdf compression without much user difficulty. Adobe's Acrobat contains an optimizer for compression of .pdf files and many third-party programs exist for the same function. When it is necessary to know how to compress .pdf files, consider individual requirements. Certain programs have certain functions and some may be more appropriate than others depending on the situation. Consider the balance between the cost of .pdf compression software and the amount a program will be used. Buying a program that answers how to compress .pdf files but also contains a multitude of unnecessary features will not be beneficial.
Decide on the Size/Quality Balance
When considering how to compress .pdf files, note that compressing the files can compromise content quality. The more a .pdf file is compressed, the more detrimental that compression will be to the quality of the content. Different programs use different methods for compression, so consider individual needs and the quality required. It is important to know how to compress .pdf files based on the audience receiving the file. For instance, giving a high-stakes client a low-quality .pdf is not a good idea, but sharing a low-quality .pdf with coworkers just to have a point of reference is a good idea.
Compress the .PDF File
Once the desired balance between quality and size is known, use the chosen program to compress to .pdf file. Luckily, users do not need to know the specifics of how to compress .pdf files, because the compression programs handle the specifics on their own. If quality degrades too much or the size compression is meager compress the file again. This means keeping the original .pdf file until a desirable outcome has been reached. This assures that accidental loss of quality will not be permanent should a mistake occur during the compression process.