Looking for advice on how to access my head voice and just general critique :)

[sanyuil]

I started doing exercises regularly at the beginning of the year and would love feedback on some of my singing

All We Do (Oh Wonder) - http://vocaroo.com/i/s0HArJyHuN0l

Attention (Charlie Puth) - http://vocaroo.com/i/s1ygMO9YIvR4

Last Christmas (Wham!) - http://vocaroo.com/i/s1SpclxgOrq2

Walking In the Air (Howard Blake) - http://vocaroo.com/i/s04ijX2aRaM1

Can't Help Falling in Love (Elvis Presley) - http://vocaroo.com/i/s1iWrHN00bgu

http://vocaroo.com/i/s1qPai5FB0xY

(alternative) http://vocaroo.com/i/s06z5mi1huVM

Right now, I'm working on trying to access my head voice, so any tips regarding that would be very much appreciated