Generally, I like the idea of giving away bitcoin as a gift.
So here's one approach for those who are still willing to give away cryptocurrency as a paper wallet, in spite of the disadvantages that Murch correctly mentions.
Here's what I did in similar situations (birthday presents to adults):
- Using an offline wallet creation tool (bitaddress.org or similar) I created a key pair, including QR codes
- printed a copy (containing both QR codes) with an offline laser printer.
- folded a 5$ bill in half
- cut the private key QR code and taped it to the inner side of the 5$ bill
- cut the public key QR code and taped it to the outer side of the 5$ bill
- taped the edge of the folded bill so it does not open (unless you cut the tape)
- transfered some satoshis to the new public BTC address
- create a gift card, including my best wishes and my offer to give technical assistance whenever needed.
- on the birthday, I gave a brief face-to-face explanation about the significance of the keys (and the importance of the private key inside the bill "envelope")
The upside of this approach is that people are used to treating physical money (bills) as an asset - they keep it in a safe place and usually don't misplace it or accidentally throw it away.
The instructions on how to use a Bitcoin private key are on the internet - for a user with the understanding of the significance of the keys and some technical skills it's not that difficult to install an Electrum client and import a private key. For the less skilled or those in doubt, they have received the promise of my assistance along with the present.
The decision if you want to keep a backup of the private key is up to the level of trust between you and the gift recipient: Under normal circumstances, I would delete my copy of the private key: When ownership changes, the new owner should be the sole owner of the keys.