You're off to a good start.
Yes, crop and resize in Photoshop. They are different. Resizing takes the whole image and changes its size. Cropping discards part of the image.
Exposure looks pretty good overall though a bit hot in some areas. Maybe dial it down -1/3 or -2/3.
De-icing (removing marine snow) would help a lot. Avoid center composition.
For macro shots I like to get lost visually in a section of the piece, versus seeing a "catalog shot" of the entire specimen.
Hope that helps.