ساعدوني!

You say it exactly as it is. No fancy grammar needed here. If you are struggling with heavy bags, say it. If you are lost in a maze-like souq, say it. It works as a standalone exclamation. You can also add what you need help with later.

Use it in any situation where you cannot manage alone. Use it when you are carrying four coffees and a door is closed. Use it if you are confused by a complicated subway map. It is perfect for physical tasks or moments of genuine distress. It is a very human, connecting phrase.

Do not use it for tiny, trivial things where you aren't actually struggling. If you just want someone to pass the salt, this is too dramatic. Avoid using it in a demanding tone. It should sound like a request, not an order. Don't use it if you are trying to be 'cool' and self-sufficient.

Arab culture is deeply rooted in communal support and hospitality. Asking for help is not seen as a weakness. In fact, helping a stranger is considered a noble duty. When you say Saa'idouni, you are tapping into a long tradition of 'Nakhwa' (chivalry). People will often drop what they are doing to assist you.

If you are talking to just one man, use Saa'idni. If you are talking to one woman, use Saa'idini. However, Saa'idouni is the safest bet when shouting to a crowd. You might also hear Mumkin musaa'ada? which means 'Is help possible?'. That one is a bit more polite and less urgent.