I think mine are a bit older than yours but I get it.
Always having food in the house that they like, nothing fancy or expensive... just crumpets, butter, cheese, some particular biscuits that we first tried on a holiday and are now [that place] biscuits.
Making a point of eating our evening meal together as often as possible and everyone taking it in turns to talk about their day.
Reminiscing about places we've been, days out etc.
Going for lots of walks to various local parks.
Making sure that 'treats' e.g. special days out, fancy desserts etc. really are treats.
Encouraging what they're good at and interested in, in a way we can afford.
Asking them what they think about things.
Telling them when I'm really happy and content e.g. 'I love it when we all sit down together to do xyz'.
Thinking together about how we can help others.
Playing family games quite regularly... Uno, card games, monopoly.
Having a 'family jukebox' playlist for in the car.
Having a few of our own daft words for things.
Doing things in all combinations of 1-1, in pairs, one parent with them both, all of us etc.
Making sure that they're still independent e.g. set the table, put their washing away, say thank you for things, make easy snacks, empty own bags etc.
Lots of hugs and I love you/I'm proud of you.
Talking things out but keeping it brief and moving on when someone's upset.
Welcoming their friends.
Doing enough of the commercial stuff that they don't feel left out, but keeping it to a minimum.