If you have a wound and you want to make Wudu, there is nothing wrong with you leaving the bandage on; rather you have to leave it on because it is in your interests. You can wipe over the outside of it when you wash the part of your hand that is not covered.

If it is necessary to put nail polish on because of some medical problems, there is a concession allowing it and it should be wiped over when doing wudu or ghusl.

The majority of scholars are of the view that wudu is an essential condition of tawaf. However, wudu is not essential for sa`i.

It is permissible to wipe over them when doing Wudu if they cover the foot completely including the ankle, and are attached firmly to the foot and were put on when the person had Wudu.  It is permissible to pray in army boots if it is clean and pure and there is no impurity on them.

Before wudu, you should say Bismillah. After wudu, you can say this du`a, “Ashhadu an la ilaha ill-allah wahdahu la sharika lah, wa ashhadu anna Muhammadan ‘abduhu wa rasuluhu.” For more, see the detailed answer.