Grocery store vinegar isn't strong enough. And it won't make the soil acidic. If you're going to buy vinegar at the store, find the pickling vinegar, that's the right strength. Use it full strength, don't add anything else, and put it in a spray bottle, you need to get the spray on the leaves, not pour it on roots.

Your best bet is to go to the feed store for the proper strength, and again, read the label to avoid the petroleum product acetic acid. If it is vinegar you can't consume, it is vinegar you shouldn't use in the yard.

Vinegar also acts like a fertilizer, and used in small quantities in a mix (like foliar feeding) is beneficial.