Hi Leslie! Each of us has a muscle group that is genetically not as cooperative as the others, sigh!
But don't let that discourage you :7
To get stronger you need to lift heavier with excellent form, eat a bit more protein to help repair micro-muscle tears, put good recovery time between your workouts, and sleep hard.
If you think that shoulders are your genetic weakness, lets do them twice per week with three days off between your shoulder workouts (not all workouts, just your shoulder workouts).
The first shoulder workout will be the one that you usually do with a truly concentrated effort on your form from start to finish
The second shoulder workout that week is as follows:
Do a full 5 minute light cardio warm up so that you have nice blood flow circulated all about and then follow through with generous shoulder stretches and light arm circles to warm up the shoulder joint. Now you are ready to start with one lighter set of 15 to 20 reps of seated (with back support) military presses to prepare the muscles and then go right to your heavier sets.
Now you are ready to take on your shoulder workout:
For all of the exercises (listed below) do the following:
Do the first two sets with the heaviest weight you can handle WITH GOOD FORM.....(it does no good to hoist with momentum or make earrings out of your shoulders just to say you lifted it). Do only as many reps as you can with these first two sets (even if its only one rep). Then do two more sets with a weight that allows you to do 8 SLOW REPS (up 4 counts (takes about 5 seconds) and down 4 counts (takes about 5 seconds) So there is a total of 4 sets per exercise.
Rest and stretch between each set.
1) Seated Military Press....Use a bench (or chair) with good back support so that you don't hyperextend your back when you drive the weight up). Palms will face forward (as opposed to facing one another) and only lower your dumbells to about ear level.
2) Seated Lateral Raise...I personally find that I need to sit toward the edge of a bench (as opposed to having my back up against it) to do these with my best effort. Beware, the slow reps are burners....no momentum allowed }(
3) Seated or standing Bent Over Lateral Raises....really focus on bringing those shoulder blades together at the top of the movement (you won't be able to go very heavy here). Yowsa, the slow reps will get you again! I find that if I am bending at the hips to a 45 degree angle I prefer to be seated. If I am bending to a full flat back (with my knees bent about 45 degrees for support) I like standing better.
4) Barbell Front Raise or Dumbbell Front Raise...imagine you are standing in cement from the waist down. Tighten the core, plant the feet down, and exhale as you lift (not thrust) the weight. You probably need to lighten up now that you lost that momentum huh? ;-)
Keep me posted on your progress. Give it 4 to 6 weeks. Good Luck!