while just these hours helping several WP users, who are clients of mine, to install some of the more convoluted plugins, I noticed that even though they are by now quite net-savvy, they still upload zips file by file at all times.
Many did not know, that e.g. such little self-secluded scripts/uploads like plugins can be uploaded fast and easy as .zip files (setting is binary), then be extracted on the server, either using one of the panels (e.g. cpanel), the shell or your FTP program. This comes in very handy when you upload a plugin which has many subfolders and subfiles.
Of course this also works with a complete software (not with updates though).
Just a thought, but it would be a good idea to include that installation method description in the help/install-readme file of larger plugins, saves people lots of time and it has been my repeated experience that few newcomers know about this possibility.