One aspect of looking fit is having those impressive veins that stand out from your arms and other body parts... So how do you get them? In this YouTube video I talk about the main contributing factors that will help you to get more vascular looking, in many cases you already have the veins but they are just buried under perhaps a bit too much body fat.
Genetics do play a roll as body fat for some people can be stored in other places than the arms, so even if you are a bit overweight, you may still have vascularity in areas like your arms and legs. Skin thickness and vein thickness can also be a genetic attribute which will play a roll in how noticeable your vascularity is.
If you have a lot of body hair, try simply trimming it! You will be amazed at how the muscle and veins will pop out just by a simple body trim.
I also believe that blood pressure plays a roll, people with low blood pressure will have less inflated veins while people with higher blood pressure will have more swollen veins, and similarly when you workout, your blood pressure increases causing your veins to be much more vascular in appearance.
Food can effect your vascularity, when I was carb depleted for my recent fitness contest I really noticed my veins flatten out, as soon as I loaded back up on carbs, my vascularity returned. So eat up for bigger fuller veins, and if that doesn't work then try a few shots of something strong to get the blood to your extremities ;)
So keep the body fat low,body hair trimmed up, carbs in your diet and your gym pump on for that Vascular look.