Make sure you have the manuals and all the bits for all those machines. you can often download PDFs of old machine manuals from the web.
Keep and eye on where the cables are running for everything. If you have to train a cable across a through route, it needs to be taped down. Use wide tape and ensure it really is well stick down on both sides.
If you need to trail a cable across somewhere, make a "table" over it. I often place an ironing borad across where a cable is running so it doesn't become a throughfare.
Know where the fuse box is and the caretakers mobile/ cell number... I had a rather stickly moment one night when we tripped the fuses and all the sockets went down. fortunately the caretaker arrived just in time so the learners could use thier machines rather than me reverting to plan B ( which was EPP!)
Really really really emphasie that rotary cutters must only be "open" as you approach to cut, are cutting and have just finished a cut. This is the one thing I nag, tut tut and scold ( yes scold) my learners about. It is so important. If you are providing the equipment the self closing ones are best as they close as you release the handle but make sure you tell people NEVER to lock them open.
Face irons away from people. but remember you may have left and right handed people.
I keep a little old 35mm film pot for broken needles/ bent pins. Make sure everyone knows where it is.
If a machine needle gets broken, make sure you have all the parts of it. stray bits can get everywhere, ijure someone later on and can damage a sewing machine.
Makesure bags/purses etc are tucked under the tables where people will not trip on them or thier handles.
Tell your student to label everything with thier own name, that way if it does go astray or wander round the room ( as equipment often does) it can find its way back to the owner.
Have the students bring some pillows ( cushions) so they can sit a bit higher at thier machine.
I alway wear slip on shoes when I teach or do workshops. I was taught to sew in socked feet (for control onthe pedal) but you need to put your shoe back on before you move about the room.
Think about using travel irons and pads on the tables for a few students to share rather than ironing bords and big irons. This keep people sitting down rather than wandering.
When you talk to the class stand at the edge of the room, so everyone can see you and no one is listening to your back.
Identify if anyone has any special needs, such as physical difficulties, hearing loss etc. I have a lady I teach from time to time who has one hand. Her husband does her rotary cutting for her so she apreciates the cutting instructions ahead of time. On occasions where I demonstrate how to make a template she is the happy recipient of the product of the demo. These are often something she would have to ask another student to help her with or get her husband to do for her. I have one lady who lip reads, so I have to make sure she is looking at me when I address the class mid session.
I LOVE kiddies drinks mugs. the ones which have the no spill tops. Even if they do spill a few drops, it is just a few drops. I have several quilts that have been saved by the tommy tippe mug! Encourage people to usewater bottles with sports tops, again even if they are left open they don't have the spill capacity.
I like glass headed pins as they are far easier to spot when spilled. Have a magnet handy for sweeping if you get a spill.
Have a package of band aids ( both normal and non alergic types) and basic first aid kit and know who the first aider is and how to contact them.
Check your sewing machine feet. If you have any that have a single hole ( as most 1/4" feet do) make sure you tell the individual using that machine not to try and zig zag withthtat foot on. Also watch the computerised machines which re-set thier needle position automatically when you turn them back on.
Always turn off the sewing machine when changing the needle, or dismantleing to remove lint/ needle fragments etc. If you are helping someone with thier machine turn it off or make sure they do not press the presser foot. Ie move it out of the way of thier foot and tell them why you are doing it. Have a mini flashlight in your pocket in case you need the light but need the machine off.
There's quite a list there and the students are not going to remember everything so you could do a little mock up in the corner of an unsafe area and ask them to spot the hazards.
That makes it fun and more memorable.