Youtube embedding

Hi All

Trying to add links to youtube paged within certain content pages of my site (www.tacticfootball.co.uk) The links work and wordpress is autoformatting when set to live so that the link turns into the little youtube player box within my page which is what I want but the box is too big and encroaching on other areas of the page. I’ve tried using codes to set the width & height etc but it makes no difference?