My tip would be to simply allow yourself time and space to think of Elliott - I always take a moment, every day, even just to say good night to Noah at bedtime with Leah. In the first year I used to dedicate a much longer period of time each day, and I would talk to him in my head, but as I moved to a different type of grief the amount of time I needed decreased, which I did not feel guilty about as I knew Noah is a part of who I am, and I do not need to consciously miss him to be connected, but the first months were definitely the hardest, and each birthday and festive occasion brings all of the original emotions of loss and despair back to the foreground.
I hope you have been able to talk to family and friends about Elliott and how you are feeling, and I hope that Austin's first Christmas was as special as can be.
Thinking of you and sending you

xx