A few others that are just as important:
Sometimes Baby will have a bad day. Maybe teeth are coming in or they have diaper rash. Get some topicals and see if that helps (rash cream or mouth gel for teething pain.)
Silliness often works best to halt crying. Get theatrical! Pretend to cry and make some noise right alongside Baby. If the crying has been going on for long you could use this as a good way to unwind. Make fart noises, play airplane, hum through your fingers and wiggle your lips. Make up a song about how mad Baby is, complete with crazy vocal inflections. Do a stupid dance. The goofier you look, the better you will feel and the more likely Baby is to join in. If Baby has to stop crying to figure you out, you are on the right track. Stinky feet almost always works. Take a whiff of Baby’s foot. Fall off the couch in olfactory outrage. Say in shocked tone, “MAN! How did you fit so much stink on one foot? Let me try the other one!”
If this does not work, or if it just gets worse, by all means stop acting like a goof ball and look for other causes. Maybe Baby has a tag poking into their tender baby neck. Perhaps their diaper tabs are poking them in the belly when they sit up. If they tug their ears or if the ear has an odor, Baby may have an earache. Look for a physical cause, like restrictive clothing, a bug bite or a scratch.
Surprise Baby with something new. For some reason whenever my wee ones would freak out (that red-faced hitch in the breathing pattern, high-pitched thing that makes your ears bleed), a cool wet wash cloth would always distract them. I did not DO any thing with it, just handed it over and suddenly they were lost in cool textures and seemed to forget why they were mad.
If everything seems fine and you have tried all of your tricks to no avail, you just wait it out. Remember Baby cries to tell you something is amiss. You are right to respond. If nothing seems to work and your patience is wearing thin, take a deep breath, smell their hair, put them somewhere safe and walk away for a few minutes (really, just a FEW). Still not working? Acknowledge your frustration. Cry if you want to. Call a friend. Sing. Breathe deeply. Imagine that you were that little baby and give yourself what you need.
Do not yell at the baby. It is OK to be mad or tired or sick of being caretaker for a cranky munchkin, but do not add to the situation with tense muscles, jerky motions or terse words. If you get to this point you need to back off. In other words, thoughts and feelings are fine and we all have them, but physical meanness toward a baby is unacceptable. If you feel violent or impulsively irritated NEVER, NEVER, NEVER shake the baby! This can cause immediate, irreparable brain damage or death. I repeat – DO NOT SHAKE A BABY, EVER.
Try not to invest yourself into their tantrum by making it a reason for you to be mad too. Sometimes you feel yucky and want to cry, and Baby does too. The object is not to shut the Baby up, but to make the Baby feel all right again and make sure they know you are there. Some babies cry a lot. Sometimes they go off because you expect it to happen. Sometimes the Baby is picking up your tension. Let them pick up your calm instead. Just remember that nothing lasts forever and relax.
It is like a rainstorm. You might be able to dance it away, or you might have to wait and let it be what it is. The sun will be back again, I swear.