Transfem

(EDIT: I should say, gender-affirming care is the number one way to alleviate dysphoria: hormone therapy, surgeries, hair removal, etc. should be prioritized and come first. My response assumes you are already on top of that.)

Some tips that have helped me:

• get your eyebrows waxed initially by a professional, then use tweezers and pluck hairs every day to maintain - this can make a huge difference
• if you wear glasses, choose women's glasses next time you get a new prescription
• learn makeup and do it even if you aren't leaving the house, it can really help what you see in the mirror (I actually went to Sephora and paid for a class, this was really helpful - I was clueless, and they helped me color match and find products that actually work on me - expensive, but helpful)
• wash and style hair, take good care of it (learn how to take care of your hair - this was a whole thing for me, I have curly hair and learning the Curly Girl Method was life-changing)
• put on a cute outfit, again - even if you're not going anywhere, it feels nice to wear affirming clothes, so do it for yourself (plenty of trans women will wear a bra & panties even at home, when sleeping, or other times others might not normally wear them); also, learn how to dress well for your body shape (most of us are strawberry or apple), how to accentuate and emphasize the right parts (breasts, hips, butt) and diminish or hide the undesirable parts (broad shoulders, belly, flat chest, etc.)
• get nails and toes done (gel lasts the longest in my experience), this has acted for me as a daily visual reminder of my femininity
• for vocal dysphoria: hold the line, spend some time warming up and practicing the voice and then try hard to not let it fall back the rest of the day
• maintain a daily skin routine: figure out your skin's tendencies, and at least get a good cleanser and moisturizer (might start with a Cerave cleanser and Cerave in the tub for moisturizing face before bed), and at bare minimum cleanse and moisturize your face before bed, and change your pillowcase once a week to help avoid bacterial breakouts; bonus points for using a good ceramide lotion on arms and legs, etc. (esp. where you get dry: knees, elbows, hands, and feet); also, start wearing sunscreen every day, esp. on your face, find a good cosmetic sunscreen you like (usually the good ones are from South Korea or Japan, e.g. I really liked Canmake's Mermaid Skin Gel, though they changed their formula)
• prioritize hygiene, shower once a day and brush your teeth (some people rot, you will feel better if you look and smell nice - pick products that make you feel feminine, I love my lavender scented deodorant, and you can get fun body washes with scents you like)
• go out, sometimes the way I felt best was when I forced myself to feminize fully to try to pass in social situations - I noticed on days when I left my house and actually moved through society as a woman were some of my happiest and least dysphoric days (even when very insecure), esp. when people referred to me as miss or ma'am. Early transition this can be harder when fewer people see you as a woman, but I still think it's good advice then, too. At the very least it forces you to do makeup and hair, etc. which helps.
• when dysphoria mounts into a crisis of doubt or imposter syndrome that makes me start to want to detransition, I found it really helps to journal - sometimes it's good just to recall memories that remind you of why you are trans, but in my worst moments I found it helpful to engage in cold analysis: looking at what it means to be cis vs trans, what evidence there would be if I were a cis man vs a trans woman, and then comparing those to my experiences. Usually after a few pages of this kind of "objective analysis", I finally get the bigger picture and realize I really am trans.
• see a therapist to help talk through your feelings, medication can also help (though HRT is often enough for a lot of women)
• if you are on HRT, cycling your weight (i.e. slowly, over months, lose 1 - 2 lbs a week, and then intentionally slowly gain it back) can really help give you curves; if you're skinny, eat - boobs are curves are fat; if overweight, gradually lose weight to lose the "dad bod" (fat distributed at the neck, shoulders, and belly), but occasionally give yourself a plateau where you put a little weight back on, esp. in the first 3 - 6 months of HRT.
• until you have significant hair removal, don't skip on shaving - I often would get exhausted from all the shaving and skip out on the weekend and it always made my dysphoria worse, don't underestimate the influence hair plays in your dysphoria like I did, shave!

Generally, dysphoria is not as bad for me when other things are going well, e.g. if I'm well hydrated, had a good night's sleep, and I'm eating healthy my skin tends to look softer and more feminine and is more likely to look "nice" to me. My mental health is also usually better, I'm less likely to spiral from insecurities and poor self esteem, and so on.

So, follow the basic steps of being healthy as well:

• eat lots of diverse and healthy foods, including vegetables (avoid processed foods like frozen nuggets or pizza, prefer "whole" foods like baked sweet potatoes, beets, beans, rice, etc.); plenty of my mental health episodes are triggered by being dehydrated or hungry - keep on top of your needs!
• drink lots of water (drink a glass when you wake up, keep water near you all day and remember to actually drink water, drink lots of water with your meals - digestion dehydrates!!, and eat lots of water-rich foods like cucumbers, tomatoes, lettuce, etc.)
• practice good sleep hygiene: go to bed & wake up at the same times, keep a strict-ish schedule and make sure you give yourself ample sleep opportunity - be luxurious with your sleep and prioritize it over all else (esp. important when you start HRT, you might need more sleep as you undergo neurological changes - it really is a puberty!!)
• get regular aerobic activity, e.g. go for a 20 - 30 minute run a few times a week; stay as active as you can - get in walks after meals, even just walking for 10 minutes can really help the body and mind
• avoid stress and engage in stress reduction activities: take hot baths, meditate, give yourself breaks from work and enough time to come down in the evenings before bed, etc.

It's less about being perfect and more about doing what you can.

Less conventional tips:

• blur your eyes a little or take off glasses if you have them when around the mirror, I find my brain-worms see a boy in the mirror the most when I have all the fine details, when the image is a little blurry, my mind is more likely to fill in the blanks and see the "girl gestalt" everyone else sees
• reduce exposure to mirrors, esp. in early transition when you look the least yourself (I promise it gets better the longer you're on HRT); sometimes this just means don't obsess, but sometimes this means taking whole days off from seeing yourself.
• spend time remembering your most euphoric and affirming moments, recall how you felt and stay with those feelings, close your eyes and replay those memories in your mind, affirm that you wish for yourself to feel this way in the future, explore what would make you feel good in the future, imagine and visualize a happy future for yourself - spend maybe 10 - 20 minutes doing this once a day. You might add affirming messages, whatever works for you.

See also:

• /u/FoxyUnicornX's tips on passing (in my experience, aiming to "pass" as a woman overlapped almost entirely with what was gender affirming and dysphoria-alleviating - the toxicity of passing culture aside, some of these tips can be helpful for feminizing, the goal here is to pass with yourself)
• /u/Jordanlilbeeb's 13 tips on passing
• anything by /u/Laura_Sandra, start with her /r/Trans_Resources wiki
• and of course, a more general resource is Gender Dysphoria Bible