Being pre-op, I'll talk about hormones, by way of my experiences.
They can be magic, for one. They help your skin - it becomes softer, and clearer. It changes body shape subtlely, as new fat gained will be allocated to places typical of women, such as the thighs, bum, and breasts. However, fat may also still gather in more male areas, like the belly. They should also slow down body hair growth, and possibly reduce or even eliminate it over time, and there are other subtle changes also.
The most significant changes are the development of breast tissue, and changes in how the fat is distributed in the face. The actual differences hormones make are very slight, facially, but somehow they seem to, all the same, be very obvious to someone who can see a before and an after.
The most important thing to know about hormones is that they are very variable. You might get lucky with one thing, and miss out on another entirely. You might not get any real physical benefit at all, but just the same, they could completely transform you. For example, I still have a lot of body hair, and it hasn't really gotten lighter or anything at all. I also developed very minimal breast tissue, which took me completely by surprise, because of how my family members are with that. However, my before and after pictures are very different, facially. I don't recognize my before pictures anymore. My facial hair was also changed, in that it started to grow more slowly, and it didn't leave as much of a shadow as it used to.
The only guarantee is that, if they're for you, they should put you at ease, and improve your mental and emotional wellbeing. This is the most powerful change, right here. A little confidence goes a long way to helping a person out.
