Bulma's Baby

Bulma's newborn....which one..(bra/trunks) i dont know...I did have vegeta in the background looking at the sky...but it looked really wierd, so i edited him out. This sketch was just another excuse to use photoshop......still dont know wtf im doing. How DO I MAKE IT SO THE LINES ARE THICKER? they seem to dissapear when i try and color.