I take half-empty bottles of shampoo, shower gel etc and throw away what's left before I come home - the toiletries really add up the weight! You could even just take the tiny sample bottles of stuff (Superdrug do a good range) to do you the first day or so and then buy cheap stuff from the supermarkets when you get there.
Suncreams weigh a lot - work out how much you
really need - one bottle of high SPF for the first few days and a couple of lower SPF for the rest of the holiday, bearing in mind it's easy enough to buy more from the supermarkets when you get there - it might be a little more expensive there but it works out cheaper than having to pay for excess baggage
Some hotels let you hire towels for the pool, so you don't need to take any of your own - even if your hotel doesn't hire towels, you don't need loads of them - one to lie on and one to wrap up in, they dry on the balcony overnight and if they get smelly after the first week there's usually a laundrette somewhere
One pair of pants or a dark skirt will go with several different tops for evening wear, and the tops you wear in the evening can be 'dirtied-out' the following day, to save on taking a selection of daytime tops. For a 2-week holiday I take 4-5 pairs of evening pants or skirts which can all be worn several times with 14-15
lightweight tops which can be worn first during the evening and then again during the day. I take 5-6 bikinis (they don't weigh much, can be washed out and dried quickly) and 3-4 pairs of shorts and/or beach skirts... and that's it!! Now, go and get minimalistic girl - think 'less is more' and you'll even have weight allowance left over for shopping coming home!