To maximize the probability of succeeding to read the disk, it is
often suggested to first attempt to create an .iso file of any
partitions you want recovered. In the case of failing to read a
partition, an attempt to read all the disk sectors saving them to an
.iso file is usually made. dd can be instructed to attempt reading a
sector more than once in the event of read errors. It can also be
instructed to ignore read errors in the case of very badly damaged
disks. Because dd is a very low level tool, it is also very powerful:
misuse can result in more damage to data. Make sure the "of="
parameter points to your .iso file to be created.

With the .iso files saved to a healthy disk, you can then try to
recover your data without worrying that your dying disk may stop
working completely while you ran file recovery software. Please, be
aware some recovery tools take a very long time to finish.

Testdisk is an interactive tool that allows you to search for lost data.

Edward

--
If you can't explain it simply, you don't understand it well enough.

Albert Einstein