Is it best to go through and delete as I import.... using command + delete? or des that actually leave the originals in my library still?
It is perfectly o.k. to browse your imported images directly after import and to weed out the technically bad images. "File > Delete Version" (shortcut ⌘⌫) will send the version to the Trash. It will stay in the library, until you empty the Trash. After emptying the Trash you will find the deleted images in the Trash bin in the Dock.
OR is it better to go though and just tag the better photos with stars? and separate those out? I will end up keeping prbaly 50 of the best.
That is what I am doing. I tag the images that I really like with prelimirary star ratings and assign the rating "9 - reject" to the ones, that I want to delete. The "reject" rating will remove the image immediately from the Browser and collect it in the "Rejected" album. This way I can check the images before I send them to the Trash.
How do you back up your original image files? Have you set a backup location in the "Import" panel? Whatever strategy you are using for the inital deleting of bad images, does not really matter, as long as you back up your imported images directly from the card, so that you have a backup to fall back to, just in case make a mistake when deleting.
good idea on tagging with rating 9. Do you have an automated action? or is that actualy a shortcut to designate "bad" images.
I haven't been backing up 'all' of my original files, work for a small paper, so the images build up pretty quickly, as long as I save the very best 40-50 on each event, I am happy. Only 2 or 3 will go in print, the rest I hang onto for potential portfolio or marketing.
I will take a look at the backup location, I can see how that may be wise, at least till I am sure I have my final picks, after that I'm happy to let all the bad images go into pixel space.