One thing I use to inform people about my hearing loss is a phone app named "Sorenson Buzz Cards". I have several short messages (displayed below) prepared on my phone which I can easily display and show the speaker. This works good in a noisy place or to inform the speaker without interrupting him. It is also useful for any short message such as a restaurant order, where is the restroom?, or here's my e-mail etc.
1. I am hard of hearing please face me.
2. I can't understand you, please write
3. I am hard of hearing – I use sign language.
4. #1 meal, no fries, to go please.
or you can type in any message you want
You can also have the speaker type in their own message to you if necessary.