An easy to add some show and go to your physique is to focus on the neck. There are few body parts that let people know you don't eff around like the neck. Most people skip training neck because they don't know where to start. Like my boy Zach Even-Esh says "quit nerding everything out in the weight room." The 3 easiest ways to attack the yoke are flexion, extension and rotation. Depending on how often you train, it is easy to add it to any session.
A neck harness is a valuable tool that is too cheap to pass up. This is also one of the best ways to work neck extension. Visit Amazon.com to pick one up and I would stick with the old school leather one because you won't want anything fancy. Try and test them out my brother bough a different nylon type and the sides would rub on his ears. Self-explanatory here. Strap some weight to the chain and bring the chin up and down. Be careful to keep tension on the neck and not totally drop the weight. To set it up sit on the edge of a bench or stand with hands on knees. The best rep scheme I have used is to hit a total of 100 reps with a light weight. Keep track of the weight, reps, and number of sets to reach 100 total reps. Let's say you start off with 15 lbs. but it takes 10 sets of 10 reps to get your 100. Weight shouldn't increase until 3 sets of 33 is easy then increase by 5 lbs. and repeat. There is a partner assisted option in which the partner holds a towel on the back of the head and applies pressure.
Neck flexion starts by lying on a bench with the head hanging off the edge. Weight is placed on the forehead and held by the hands. Fold a small towel to cushion the head. Extend the neck until a comfortable range of motion not too far. After the chin opens your neck you must flex to tuck the chin to the chest. Same here on rep scheme go for a total of 100 reps with small increases in weight. The partner assist option involves a towel across the forehead with applied pressure.
Rotation is my favorite just for the looks I get when I pull this one out of the bag. Attach a band to the rack. The band will be held in your teeth so have a towel no one likes the taste of rubber. Walk away from the rack with band in mouth until desired band tension. This is easy to adjust. Turn the head away from rack and return to start. Hold the contraction for a count and repeat. Still aim for 100 reps but smaller sets.
Not training your neck sounds like a dumb idea. Train 3x a week and add a day of flexion, extension and rotation between sets is easy. Following this routine has put a solid 1.5 inches on my neck with no significant extra time added to my workouts. To see progress treat the neck like a lady, not some girl on Prom Nite. Slow and steady.