HRT (and transition) is a marathon, not a sprint. The biggest changes will happen in the first two years, but you will still see changes 5 years in and even beyond that. External factors will also cause a lot of changes during that time.

For fashion, you mentioned high waist, that definitely helps. Anything that creates curves helps. I like dresses and coats that have a waist cinch.

As long as you're comfortable, you're doing well and don't need to fret about the little details.

Signed, 11+ years here

Honestly, you don't do much of anything except wait when it comes to the results of HRT. You want to keep an eye on your levels and make sure your doctor isn't giving you too low a level, but otherwise, it's just a case of wait and see.

HRT will cause new fat you lay down to lay down in different areas. But it takes time for everything to adjust and you might be able to nudge it here and there, but basically, it takes as long as it takes.

I'm about 8 years in myself, and not much is changing these days (well, except for aging). But things were changing until around 5 or 6 years in.

But, there's lots you can do that isn't just waiting for HRT. These days, I pretty much don't do much of anything special in terms of getting dressed up and super fem, but my first couple of years were pretty much constant experimenting. I got a lot of good results from learning how to do basic makeup. I had no idea what my style was, so I just fucked around and found out (in a good way). That's what you need to do :)

Here's my two cents, approaching 20 months on HRT. All based on personal experience, I'm not a professional. If you disagree with some of this stuff, that's fine, we're not all the same.

• I'd say you can just go look for a basic women's workout routine. Most women who work out focus on their glutes, legs and abs/core. If you don't want to go to a gym, find Pamela Reif's weekly workout plan on Instagram/her app and just stick to that (what I did).
• Nutrition is just as, if not more important than the workout. Eat healthy, protein-heavy and most of all: enough or more! If you starve yourself, you won't gain. I personally eat a good 30% more than before HRT and still don't gain weight. A burger / something unhealthy more is better than eating too little for the sake of eating "clean". Just follow fitness nutrition advice here, there's no special "transition diet".
• Breast development is 100% genetics, so whatever growth you experience is just normal/correct. There's no good or bad. Remember that cis puberty takes 5+ years and many trans women experience breast growth past year 1 or 2. When you're a year or so in, you can look into progesterone.
• I personally ditched jeans completely a few years ago and haven't looked back. But that isn't a must. Make sure high-wasted things really are high-waisted, not mid-waist and just higher up than you're used to. Real high-waist is belly button level or above. Look for ribcage jeans. Mid-waist tends to look weird on bodies that aren't very very hourglass-curvy. The waist of a dress is often at the bottom end of your ribs. This is normal and what looks good on most people. The best fashion tip is to wear what women around you wear. Look at women your age in your area/workplace/school and just copy them. Or, even better: go shopping with female friends whose fashion style you like. Don't order online. I know stores that just cater to women are a bit awkward if you don't pass, but trying stuff on and feeling it etc. is so much better than shopping online. And if you're scared: take a friend! This varies, of course, depending on where you live. I live in a left-leaning city and have never had any problems shopping in person when I didn't pass.
• Experiment with different fabrics. I've grown to love velvet-y and silky things!
• Women also tend to wear more accessories than men. Rings, necklaces, chains, charms etc. Collect things you like and get used to wearing them. Rings feel weird at first if you're not used to them, that's normal.
• Experiment with your silhouette. Find out if you're a big top-small bottom or a small top-big bottom kinda girl. Go big-big or small-small. Find out what you like. Use your waist and accentuate with belts. Go second-hand shopping and buy the weird clothes that spark joy. I started dressing fem 2-3 years before I started transition (so now about 4-5 years ago) and have only just found my style. Remember: cis women do this in their teenage years and are a bit ahead of you here! Don't worry! If you're unsure, ask a friend whose fashion you like if an outfit looks good. If you don't have a friend like that, ask young women in second-hand shops. They're nice, I promise.
• On behaviour: Women tend to take up less space in public (the way they sit and move). Female friendships are very different from male friendships, much more intimate and unhinged. You can tell a good female friend everything. You're allowed and encouraged to be open with your emotions, this is nice. Confidence is key. If your behaviour is confident, people will accept you more than if you're hesitant. Confidence is often the difference between "weird" and "mysterious/interesting"
• Bonus thought: What helped me a lot was making my apartment more "fem" and cosier. Candles, plants, plushies, softer colours. This makes me feel better and more in line with myself when I'm home.

What the others said is true, but:

• Exercise is just good in general, but also burning fat will burn fat from the "non-fem" areas, which won't get replenished
• I heard salmon is good? Because of the fat? Not 100% sure
• I've got 70A/B (EU sizing) in 10 months, so you've got more than me there :P but anyway breast growth is just genetics + nutrition + time, don't focus too much on it
• I found painted nails help and are fun? I lile black because it's the default "alt" color so ppl can see me as a guy and still not be weirded out too much

I may be losing my shit but I swear my boobs have grown each time I get off. So, heighten that oxytocin I guess

• Curves: Curves take a lot of time, because fat redistribution is a slow process. I've been told it kicks in after several years. Excercise helps, and I think it's mostly because it improves your metabolism. Despite what some have said, cycles of (unintentional) weight loss and gain absolutely did not accelerate redistribution for me.
• Diet: Honestly, just eat what's healthy. Hydrate. Get good quality sleep. You're a growing young woman, and they don't call it "second puberty" for nothing.
• Breast Growth: Congrats on the cup size! But I can't say if it's slow or fast. The spectrum of "normal" breast growth is wide and nonlinear (growth spurts). If your nipples hurt, then it's working, so celebrate and treat yourself to ibuprofen and a hot pack.
• Fem Appearance: Get hair advice from a trans-inclusive hairdresser. Good conditioner made more difference than I thought. Painting my nails is a special euphoria for me; even when I feel like a ceramic construction material, I can look down and see pretty colors on my hands. Try on lots of clothes, including stuff outside your comfort zone.
• Mannerisms: Fem-coded mannerisms are a wildly deep topic. I'd suggest looking at photoshoots to see what they're doing with their hands, how they touch their faces, and how they carry themselves. Important: try to only look at photoshoots of people whose bodies remind you of yourself, and remember that magazines are designed to trigger self-loathing spirals in their readers.
• General Advice: "Try everything and keep doing whatever felt good" seems to be a winning strategy. You have a new body, new hormones, and a new outlook on life. Who knows what kind of person you could be. Discover yourself!