Looking at my own travel first aid kit, the contents of which have been refined over the years I'd also suggest the following in addition to the suggestions you've already had.
If you're planning to do any sightseeing (or just taking those new sandals with you!) you might find that you'll be glad you also included some blister dressings. They'll promote quicker healing than ordinary plasters will.
If going with kids or doing any sort of activity were any of us might fall over, I also always include a couple of non-stick and/or colloidal dressings which are larger than ordinary plasters because they can be really handy for grazed knees etc.
A small roll of microporous surgical tape has many more uses than just keeping plasters on kids who are in and out of the water. For example, it did a great job of keeping my camera battery compartment closed after I dropped it one holiday and damaged the catch!
There have also been a couple of holidays where a small crepe bandage has come into its own for minor wrist and ankle sprains. A good alternative is an elastic tubular bandage Cut into smaller lengths it also makes great if inelegant hair 'scrunchies' in emergencies!
I also take a small pair of tweezers (good for removing splinters etc ) and a small pair of scissors but if you add these remember that the kit will need to go into your hold baggage as they'll get confiscated if packed in hand luggage.
SM
and cant think what else to add, also is it best to have in hand luggage or 'boot' luggage??
