Being responsive to the mother and really listening, taking seriously (and acting on) what she says - concerns, worries etc.
Being an advocate for the mother when necessary.
A caring approach - that 'human touch'. Cannot underestimate how far that goes.
Continuity of care as far as possible.
These are very personal to me. I had a very bad experience of MW 'care' with my first pregnancy, labour and birth.
During my pregnancy, I had: my excruciating SPD and associated depression brushed off as 'part of pregnancy, unfortunately'; a sweep literally forced on me; and I never saw the same MW more than once.
During the labour and birth I was treated like a piece of meet. Midwives did not even introduce themsleves, smile, talk to me or explain what they were doing when they woke me up in the night for an internal examination or to take bloods (during a long induction). A midwife gave my baby formula without consulting me straight after birth and discouraged me from attempting to breastfeed as it 'wasnt working' ...about 6 hours after an emergency c-section.
In the four days I was kept in afterwards, I saw a different MW every time the shift changed. Not one of them was polite or friendly. Not one of them took my concerns seriously (what shall I do with my baby when I need to use the toilet and have a drip attached and am a new, nervous mum? I need my anti-d injection, its been nearly 72 hours! I need some BF support! etc - all ignored, fobbed off or treated with impatience and even contempt).
My second birth was different. Consultant-led, but the MWs I came in to contact with were fabulous. I felt they cared, they were professionals and they were passionate about their roles.
I was admitted for an emergency section when I became ill at 37 weeks and the same MW stayed with me, advocated on my behalf to the Consultant (who was dithering about whether I needed an emergency section...I remember her saying 'this woman has reduced foetal movements and is in distress, Mr X. I really think you need to reconsider.' Excellent! :-) She came to see me the following day as I was about to go in to theatre to wish me luck. The MW in theatre was like an angel. Smiling, warm, held my hand and was so supportive of my BF issues afterwards. The after care was completely different, even within a (different) very very busy London hospital. Every MW was caring and tried to be as attentive as possible, given their busy schedule, and there didnt seem to be such a chaotic rota system - fewer agency staff, saw the same two or three MWs over 3 days. I felt listened to and valued.