Do you mean practical things you can do to help ?
Get them used to walking home on their own now (or using public transport) - on a route that is familiar with their mates they know well
Give them a doorkey and let them get used to using it (all locks are a bit different and the key needs to be wiggled a different way)
Make sure they are thinking about what day of the week it is, and what they need to take in tomorrow - swimming kit, flute, football boots, whatever before reading MN I assumed everyone would be doing this by Yr6 but apparently not
Think about after school care - will they be alone in the house for a bit, before you get in from work / whilst you are collecting younger siblings from Primary? - get them used to being at home on their own for a bit, and build it up gradually (again, I used to assume everyone would have by now, but apparently not)
Have lots of conversations along the lines of "What would you have done if......." (You forgot your key / the bus didn't turn up / you felt uncomfortable with a person standing near you at he the bus stop or who you thought might have been following you / I didn't come home when you were expecting me / the school closes early because of snow or boiler breakdown / etc.,etc)..... not all on the same day
, but start them thinking for themselves now.
In the Summer holidays, practice walking the route, or getting there on the bus. Have a look at alternative routes - what if a mate lives down that rd - 'look, it's OK you can then cut through here and you are back on this route' type convos
Ask them what they think is a good idea / reasonable rules re going to a friends house or them coming to yours - show them you are recognising they are growing up and will be making more decision of their own.