Last year I got all the adults the same gift, nice quality but small and not expensive - imagine a wooden pencil box or something similar. It was only around 10 quid each, but it meant I only had to come up with one good idea not loads.
Use a sharpie to write on the paper, don't faff about with labels.
Cheap and cheerful paper looks just as jolly as the pricey stuff and it's only on for a matter of minutes anyway.
Any paper with glitter on will resist sellotape so avoid.
Turkey is actually minging, no one likes it really, it's got quite a strong gamey smell which the kids always moan about so this year I'm just doing a decent organic chicken.
Don't bother with a bronze triple platinum organic turkey the size of a labrador unless you are a brilliant cook because they're really fucking easy to under or overcook - sometimes both! And they cost more than the new Fiat 500.
If you get one and then go to the trouble of soaking it in salt and orange peel and expensive herbs and spices for a month bear in mind the previous tip and note that if you are a crap cook it'll still be dry chewy cardboard on the plate, albeit slighty fragrant chewy cardboard.
Other tip is don't presume online shopping is simpler. Actually what you then have is to be in/go collect your parcels, unwrap the boxes and then go out to get your paper and sellotape etc. It's actually far more efficient to do one trip into town armed with decent list - it gets it all done and dusted in a matter of hours, not days. And you don't end up filling your recycling bin with boxes and packaging just before the big day!
I put my plastic tree back in its box complete with baubles in January and so my decorating this year will involve retrieving box and taking tree out.
Real trees are a pain in the arse so if you get one make it a small one that might realistically go in your green bin without having to get a saw on it.