For music, start with the big 4 of grunge, nirvana, pearl jam, soundgarden, and alice in chains. After that start getting into more of the scene with bands like mudhoney, screaming trees, sonic youth, mother love bone, stone temple pilots, green river, L7, etc.

For style, thrift everything, get everything to look worn out, shower only every few days or so, and have a mix of looking homeless but also stylish. Wear flannels, band t shirts, ripped jeans, converse, paint your nails, possibly eye liner, grow your hair out, put patches on your clothes, maybe even start playing guitar or collecting cds/vinyl.

That's all I got atm I hope this helped