Good advice there from Karl.
If you are not expwereinced in hill walking or mountain walking, a good way of keeping yourself safe is to accept that you are always more tired than you think you are: don't get caught out by taking on too big a cllimb or walk.
Also, keep mobile phone batteries charged up, always tell your hotel, hostel or campsite where you are going and when you expect to be back; note the emergency number for mountain rescue, which is 999 in UK - you will be asked 'which service do you require?' to which you should reply 'mountain rescue'.
You should always be aware of your approximate 6-figure position on an Ordnance Survey map, in case you need to give directions to recsuers.
Sorry to sound so gloomy Mirela, and I'm sure you'll have a wonderful time, but taking these precautions makes sense and makes your trip safer.
Check out this link which has some forums whetre you can ask more about equipment and conditions:
http://www.munromagic.com/MountainInfo.cfm/30