No! It's not wrong to look attractive. Your body is the temple of God and when you are exercising, watching what you eat, and wear clothes that fit right you are in God's good side.
It's when you are obese or too overweight, you eat lots of junk food, and wear clothes that don't fit (either too tight or too loose) then it's a bad thing to God.
You must keep your body well and healthy (inside and outside, okay). So, exercising, watching what you eat, and wear the right kind of clothes are great with God. It's okay to look good, inside and out.
But of course, never be obsessive with it and don't go to extremes to look attractive (i.e. bikinis, tiny t-shirts and/or tank tops, short shorts, etc.). These kind of clothes are no-no's to God.