Personally, I consider (significant) nausea and vomiting from alcohol as an indication that I have drank too much or too quickly. Obviously, drinking less/more slowly is the way to avoid these negative effects.
Additionally, here are some other things you may want to consider:
-Drinking on an empty stomach seems to cause more irritation than drinking after a light meal. Nothing too heavy though, drinking while feeling stuffed could easily cause nausea as well.
-What you drink seems to matter. Acidic or high proof drinks are more prone to stomach irritation. So, try drinking beer instead of hard alcohol or wine (wine is acidic). If having mixed drinks, avoid using citrus juices or cola. Coca-cola has a pH of ~2.5 for example, which makes more acidic than orange juice.
-Keep your non-alcoholic fluid intake in mind. Alcohol dehydrates you due it's diuretic properties, even when drinking beer. You need to make sure to have some water between drinks. Have a glass of water after having 2-3 beers/mixed drinks, and try to have a glass of water in between each shot of hard alcohol. The constant peeing from this is annoying, but you feel much better if you stay properly hydrated, especially the day after.
hope that helped, good luck!