Is it artificial things or fragrances in hair products that you're allergic to? Just out of curiosity. I know there's some all natural products (even for men, though I know there's arguments that they're not any different between the sexes at the same time it can be a little esteem boost regardless). Just wondering if there's something that might work for you because I think using product (if possible) could help.
Though, either way, yea cleaning up the back and sides and having it longer on top will help a lot. While not inherently a female thing, whispy hair on the sides could give the wrong cue to people.
As far as the jacket goes, a couple things you could try such as not zipping them up all the way (unless bitterly cold, in which case consider a good scarf either first or in addition to) would probably help you out. If there's lines on them, whether different colors or sewn like that one, try more horizontal lines or if they are in a v-pattern then something more angular. They're illusional tricks to broaden or give the impression of a more v-shape to the body. You're a thin guy so tricks like that could well help people lean more toward masculine than feminine when looking at you.
Also, avoid shirts or jackets that seem to tuck in at the waist (in the middle). That's a general rule of thumb for most FTMs.
Just some things to play with and see if they work for you.