I know its not so much a skill, but its incredibly important that you are and remain in good health. When you are sick, you have to suck it up. There is no one else to take care of the kids. They don't understand that you cant carry them, of play with them or maybe even leave the bathroom.
Try to have backup for any and every situation but remember, no matter what, you are the one they want. Ask for help, don't wait for someone to offer it. I'm a single mom (by choice) to twin boys. I've learn to ask more now. I didn't turn down offers to help, but its only recently that I started to outright ask. People will say no if they can't but Im amazed at how many do help.
Most other advice applies to any parent, single or not, about patience, consistency etc.