Being good at smelling and tasting won't really help improve your physical performance in anyway ('gee look at me I'm the incredible Tasting Man (and I say gee)' - just wouldn't work). Still they're valid senses and an acute sense of smell at least can give you important cues regarding your surrounding. To improve both increase you intake of zinc, which has been shown to be beneficial in this area. It can be taken as a supplement or found in beef, oysters, baked beans and other foods. It also help you heal wounds and fight infections. So get it in you!
You can also 'practice' taste to improve sensitivity as demonstrated by chefs and food critics who can taste very subtle differences in the ingredients. Again it simply requires you to concentrate more on the sensation of the taste as you eat and try to identify the individual flavours. Every time you eat it becomes a 'taste training' session. It's a tough job but someone's got to do it...