Let your subject fill the frame. Bring life to the scene. Pictures of buildings or architecture will be more interesting with people in them. People give architecture a sense of scale, as do children, pets, birds. Forget thinking you need all the latest equipment, but if you buy one thing, buy a good tripod.
Most blurry pictures come from camera shake.
Ignore the old adage that when taking portraits, the photographer should have the sun at his or her back. That just gives you washed out faces of people squinting. Count to three then take the picture on five or six, after the fake smile has gone. Or try taking two pictures in a row, one of the fake smile, the second of the genuine one that usually follows. It's easy to avoid that frustration by keeping a camera handy.