Avoid power struggles around patching.
Use a timer to indicate when the patch comes off. This makes the timer the "bad guy," not the parent.
Consider having a rule that only parents touch (put on, take off) the patch (e.g., "When the patch is on, only Mom or Dad touch the patch.")
Use positive language and say, "The patch stays on until 2:30." Saying "Don't take the patch off," is like telling the child, "Don't think about elephants."
A parent may spend 10 minutes with the child each time the patch is put on doing an activity that is fun for the child, as it takes about that length of time for the brain to "regroup" and begin using the weaker eye. See Make Patch Time Count! for suggestions.
Some parents have had success with a reward calendar, marking each time the child wears the patch as prescribed.
Try to minimize skin irritation when using adhesive patches. This kind of patch occludes sight better than those with elastic bands or patched glasses.