do you have a list, know what to buy for each person before you start?
Or
Do you wander the shops and see something and think that'll be perfect for x?
or
Do you wander the shops and see something you really like, buy it and then try and work out who to give it to?
I'm too much like the last option, have just meandered round the shops in my lunch break and bought three presents with no idea who I'm going to give them to.