If you are going to investigate microorganisms, then the first step should be fixation, followed by dehydration with alcohol (as described by Sarah), and final step of dehydration – CPD (critical point drying) of pellets of treatment with HMDS. Gold-palladium or platinum coating preferred for imaging. If you are going to study elemental distribution (EDS), then carbon coating is much better and you maybe can use air dried specimens. Specimen prep depends very much on your task.

Thank you very much the detailed and quick answers, truly researchgate rules!:)

Pls. see the attachment for detailed procedure.