Hello! I'm happy to hear there has been some improvements and your open to begin some independent sleep. Hopefully it all works out wonderfully
Some examples for a relaxing atmosphere... It really depends your LO! My baby for instance, is considered a "touchy" baby for sleep only. LESS is more with him. I take him upstairs to put on his pjs, I add some lavender oil drops on his pjs (just a relaxing scent i personally enjoy so I scent his pjs slightly with it) then I simply nurse, in his dark room, with ocean sounds (white noise. He took to it well plus it helped drown out his loud brother in the earlier months haha! It soothes him!) aaaand then when he's done I just lay him down and leave.
Many BT routines consist of a warm bath, lotioning up, pjs, one last feed and some cuddles/story time. I personally don't do all that b/c it didn't work for my baby! A bath OS him and BT would end up being a disaster. I tried for days until I accepted it wasn't for him haha! DS1 on the other hand had and NEEDED the long routine... I used to put his pjs in the dryer to warm them up so after his bath he was nice and toasty hehehe!
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...so it really depends but those are some examples. One thing i would def consider is turning down the lights, dimming the house, lower volumes or turn off televisions etc...I feel that also sets the tone for them so they know what's next.
Tips for hotel rooms and babies.... Don't you worry! It sometimes turns out better than expected so stay positive! If you stress, baby stresses! Enjoy your vacation! Things that help are all of the above or whatever you choose your BT routine to be! You see, the routine sets the mood and let's them know what's next. When you put them in their baths, for example, they know BT will follow soon. With my LO, white noise is our magic. That's his trigger to know, it's time to sleep! The same goes for our naps! When we are out and about, I have an app for the white noise and I turn it on, stick it on the side of the stroller, cover him with a blanket to block out distractions and lights...he just knows and he's out. That's how we do on vacations! Stroller naps like that! ....another thing WE do on our vacations, I always take a dark sheet or blanket with some push pins... I cover the bedroom window (some windows don't come with blackout blinds or shades so just in case!) so I can make the room pitch black
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...!
Hope this works for you! Many hugs!