If you haven’t already, download and install the completely free Disk Drill Basic. Since you want to recover trash from your Mac’s internal hard drive, it’s better to install it on an external drive (and use Portable Mode). This way you’ll avoid the possibility of overwriting your lost files when you install the software.
Disk Drill is an ultimate Mac Trash Recovery app that will do its best protecting your documents with its unique capabilities. The app offers Guaranteed Recovery and Recovery Vault options. Guaranteed Recovery keeps an eye on all your files and if any of them are moved to Trash the invisible copy of this file is saved to ensure its successful recovery from trash on Mac any time. Recovery Vault sketches a "map" for Disk Drill to find lost files.
Use Deep Scan to be efficient even in the situations when almost no file structure is left. Even if the files were moved to Trash quite some time ago Disk Drill will apply its best knowledge of file signatures to locate the correct ones and bring them back to life. Files like XLS, DOC, AVI, MP4, JPG, and others are pretty easy to recover from emptied Trash on Mac when the needed signatures are found.