I think their is no problem comes when we using XML rules.Because XML has no pre-defined tags.so, it can easy implement and made logical arranged data.Some basic rules of XML given below.Keep in mind when you creating any XML document.
Rule1: ALL tags that you open should have been closed.Like:<Welcome>......</Welcome>
Rule2:XML Tags are Case-Sensitive.So,if you create tag like:<Welcome> than you can\'t closed this tag with </welcome>.You should write </Welcome>.
Rule3:XML element should be properly nested.
Rule4:Document should have a root node.
Rule5:We should the attribute values.