And try to have patience as it will in almost all cases take longer to have a conversation. Make sure there is plenty of light. If you are outside in the daytime, make sure there is some kind of shade so the glare from the sun isn't as obvious. To get their attention, you can either wave your hand, tap their shoulders gently , flicker the lights, or stomp on the floor if it is wooden and carries vibrations. If you are a male, be aware that your facial hair can have a dramatic influence on your communication with the deaf person.
Some people can lipread a person with a mustache and beard, other simply find it impossible.
Don't take it personally, and don't give up but try other ways to communicate. In most cases, this simply doesn't work. Even though some people can lipread very well, such as Heather Whitestone or me, lipreading is still imperfect. Try not to have big conversation shifts. Wherever possible, minimize the amount of background noise.