Hi Richard,
If you'd like some constructive feedback, it helps to provide some information - here's a link to some ideas;
How to Get Effective Feedback for your Posted Images
It also helps to have all the images "inline" - like the last one was, I believe you
should be able to Edit your post (between each viewing of the thumbnail) and paste the links in via Insert Image, but I'll do it this time.
Anyways, about the pictures ...
Unless such pictures are taken for a specific scientific purpose (e.g. ID via some obscure body part/marking) - as a genral rule, it is always a good idea to have the eyes/face visible - either that, or go so close it becomes an abstract.
#1 does have the tail to attract hold our attention, but it isn't as sharp as it might be
#2 is the back end of a large spider and is perhaps too tightly composed?
#3 is a great composition, but we can't see the face or anything to hold our attention, nice lighting though, I like the bright rim on the right lifting it from the background
#4 can't think of anything to suggest,
if this is a PP crop, I might play around a small amount with the precise framing, but otherwise it's good
Actually they're all much better than "good" technically; white balance, lighting, exposure - well done.
Welcome to the CiC forums from ....