I always go in this order: Garlic/ginger/chili/spring onion whites
This is to infuse the cooking oil with these flavours.
Cook for short amount of time
~30secs.
onions
/peppers/carrots/harder veg
These need a little more cooking that the other bits, so I give them a bit longer.
mushrooms/sugar snaps/soft veg
These need less cooking, so bit less time.
bean sprouts
I like these to be a bit crunchy
so add them right at then end and basically just warm through.
If I'm using bigger veg like broccoli/cauliflower then I do them separately to the other veg.
I use a little of the chili/garlic/ginger and fry that for 30 secs, add the broccoli fry for another minute or so just to brown the florets, then add some water, turn down the heat and put on a lid, to steam the broccoli.
Once its done I remove to a separate plate the add back in at the end.
It basically depends on how much you like each veg cooked.
If you prefer your peppers crunchy, put them in nearer the end.
cooking.stackexchange.com/users/210/Sam Holder
All the advice above is good, but let me add one more thing to consider: if you don't have a wok burner with the power of a fighter jet, you might want to not cook everything together at all.
It often is best to cook one or two ingredients at a time, in a thin layer over the highest possible heat, until they are 20 seconds short of done, and then remove them to a bowl temporarily.
When the last ingredient is just about cooked, add everything else back and then add the sauce, stir a couple of times to get everything back up to temperature and serve.
cooking.stackexchange.com/users/1393/Michael Natkin
A general rule is put harder ingredients in first as they tend to require more cooking.
Things you can eat raw can go in very late as the crispness can add to the meal.
So from your list, something like this: Onion
For a little while Jalapenos (if not pickled) Mushroom Bell peppers Sugar-snaps bean-sprouts
It mostly comes down to personal preference.
Some people like soggy stir fries and others like nearly raw onions and chillies.
cooking.stackexchange.com/users/1230/Jeremy French
The general rule is to put in aromatics first--stuff that contributes good smells.
Traditionally that includes garlic, onions, dried spices, and celery.
In oil,of course.
Then the hard to soft rule applies.
The general idea is to have all of the food 'ready' at the same time, despite differences in cooking time.
So you give the harder items, i.e. carrots, longer.
More cooking time is required for items which have starches which need to be broken down (potatoes, carrots) or a fibrous structure that needs to be broken down (broccoli).
Proteins are a separate category and it depends on the amount of connective tissue (cubed beef, more time) or delicacy (lobster, less time).
Either way, you don't want to overcook meats.
Last, add ingredients that you really don't want to overcook, like fresh herbs, bean sprouts, lighter greens, lemon juice.
cooking.stackexchange.com/users/1443/Ocaasi
There is absolutely a better way than just adding everything together.
But it depends, in part, upon your tastes.
I like my mushrooms very well done, so I will toss the mushrooms and onions in together first.
Sugar snaps, bell peppers and bean sprouts
I like nice and crisp
, so I'll toss them in last just to heat them up.
For just a minute or so.
The jalapenos can go in any time depending on how much you want their spice to absorb into the oil.
The earlier they go in, the spicier the whole affair will be.
With other ingredients they may need to go in earlier or later depending on how much they need to cook and how well done you like them.
For example, things like carrots, broccoli or cauliflower may need to be blanched before they go in, or go in much earlier than other things.
Spices such as garlic or ginger should go in first or very early
so they have plenty of time to infuse into the oil.
It really comes down to the ingredients and your tastes.
Try adding things in different orders and letting them cook for different amounts of time to see what you really like.
cooking.stackexchange.com/users/438/Daniel Bingham
You add some oil into a Wok first at a temperature around 350 degrees Farenheit for 3 minutes.
Since the time for Stir Fry of the remaining ingredients is quite short, typically less than 7-8 minutes, you want to add the spices first (fresh garlic and ginger for 1 minute).
Then, it's best to have meats or tofu finely sliced about a 1/4 inch thick.
This allows it to cook evenly and thoroughly.
Then the remainder of fresh veggies can be added (I've experimented with adding frozen pineapple chunks), after tossing them with some soy sauce, peppers, or other varieties of stir fry marinade.
If you prefer certain veggies cooked more thoroughly, or if you're using frozen veggies, you might consider adding them before the fresh veggies.
Finally, to reduce the excess amount of moisture, towards the very end, I'll add some previously cooked rice.
cooking.stackexchange.com/users/54195/nhunsaker
I make nice stir-fry with bell peppers, mushrooms, onion, sugar-snaps, jalapenos and bean sprouts (and anything else that might be handy and in danger of being unused before it expires)  I tend to chuck everything in together on a really hot wok, but is there a better way?    Will adding the ingredients at different times make a difference? If so, what's the best way to do this?    Thanks
What's the best order to add ingredients to a Stir Fry?
cooking.stackexchange.com
<asian-cuisine><wok><stir-fry>
cooking.stackexchange.com/questions/3420
cooking.stackexchange.com/users/92/Binary Worrier
A general rule is to add harder ingredients first to allow them to cook longer, but espeically if your burner is not very hot it may be best to cook ingredients one or two at a time until almost done, then transfer to a bowl until later. It is best to cook the harder ingredients first and then add other ingredients later on.
It is best to cook the harder ingredients first and then add other ingredients later on.