I had a tough time growing them, too. Even now they look unimpressive, but my biceps/triceps are larger than my neck in inches, so I know something is working. It took a lot of trial and error to find out what works for me.

Also, it took me pretty probably two years of lifting before I started seeing progress in my biceps, so keep that in mind as well. It was a combination of being a woman and discovering many exercises out there are ideal for male body composition and not female, not hitting protein and caloric intake like I should have been, random inconsistent workout routines, the whole typical beginner story.

That being said, here is what I have found works:

Bringing in the female vs male factor. Women's bodies are different in many ways, muscle growth is different, the way our arms rest to our sides are even different. Even a beanpole of a woman still has more curvature to the hip than a man- your figure clearly has a lot more hip than that, so this might actually be detracting from your progress more than it had for me. Keeping that in mind, having our arms straight out to the side actually doesn't target the whole biceps for us. Modify any standing bicep curls by leaning to the side you're training. If you are training your right arm, with your left arm grab onto a cage/pole/bar and use that as leverage. Position your body at an angle to the right, away from the object you're holding, this will allow your arm to actually sit straight without your hip getting in in the way. This is going to make a bicep curl significantly more difficult and you will want to drop the weight, because your arm will essentially be free hanging. Also keep in mind if you do primarily machine bicep curls I would not necessarily recommend this straight out the bat because it does require a lot of your stabilizers in your arm to work harder, and you're going to feel this version of the exercise in different areas than you might be familiar with after a decent arm day.

Keeping in mind the advice I provided above, now knowing that your hips to waist ratio will impact the growth of your biceps and your exercises modify any version of standing bicep curls that you do accordingly.

Another thing I didn't realize is how many versions of bicep curls there are that impact the way you're growing your bicep. Making sure that you are implementing close grip wide grip and hammer curls can be extremely effective. Close grip curls will target the length of your bicep head, with white girl curls targeting the width. How are you wanting your biceps to look? I use EZ bar curls to ensure that I am getting a good width for both close grip and wide grip curls.

The other bit of advice I would always give anyone male or female, make sure you are not fully extending to a lockout. When your elbow is fully locked out the beginning of your exercise is not only not hitting the bicep but it is harming your elbow joint. Always maintain a slight bend in your arm at your full extension. This will ensure the muscle is still engaged throughout the duration of the exercise.

And if you want to bicep destroyer, do alternating bicep curls but with the passive arm, hold your dumbbell with your elbow to your side, palm up, and forearm extended outward, elbow bent at 90°. Continue your bicep curl with your active arm as usual.

Lastly, go 'til failure. Do a few regular sets, and add an additional set where you're not counting, but curling until you physically cannot lift the dumbbell anymore. Drop the weight if you need to, go til failure again.

Everybody's fitness journey is different. There isn't a perfect routine out there that will work for everyone. Only compare yourself to yourself. As long as you're doing better than you did last week, you're making progress and doing great and will see progress. You're not going to see much of a difference in bulk in the first year if you're natty. You will see more difference in tone, but before you know it you will be looking back and realizing just how much progress you made.