It depends why they are dry, that will help in finding the best remedies.
Have you seen an eye specialist about it?
I get really dry eyes (to the point of getting blurred vision) from having rhumatoid arthritis and possible Sjogrens and meibomian gland dysfunction. The latter is where the oil in my eyes is thicker than it should be (like cold olive oil apparently) and blocks the ducts. I have also had episcleritic recently in both eyes. The area around my eyes gets quite swollen too.
I have been prescribed drops from the eye hospital (Celluvisc though been given some different ones to try so I can see which help the most) which are preservative free so more suitable for long term use. I also have lacrilube which I use before I got to bed (bit like the thicker viscotears) and they have just put me on a course of antibiotics to try and help the gland dysfunction.
I also do hot compresses and bought and eye bag off the internet which is brilliant as it's like a big eye mask you warm in the microwave to heat up the oil and unblock the glands. I also do massage to help the glands unblock. My rhumatologist said that the medication I'm on for my arthritis should help it too though the eye clinic said I will need to use eye drops and lubricant long term. My tears won't stay on my eyes to keep them hydrated, they evaporate almost immediately apparantly.
It's worth knowing the cause, if you have lack of tear production, poor quality tears, gland problems, blocked ducts etc... as I think different things can affect different layers on the eye which help retain moisture on the eye etc...
Enviroment can make a difference, keep out of strong drafts or breezes which can dry your eyes out, also some conditions can make them more sensitive to light so I have a hat with a peak at the front handy, sunglasses too. Fresh air is good though - hot dry enviroments can make it worse - I struggled a lot recently at work as everyone wants the windows shut as it was cold and with the heating on it doesn't help.
Keep well hydrated, I've heard Omega 3 can help too.
Stay away from contact lenses and eye makeup and anything else which could irritate your eyes.