Miss Orchid Girl has some good information... and some not-so-good information. (No matter what she says, don't use peroxide on roots - it damages them - and purple markings on rhizomes don't mean that the plant has fusarium. ) Do ask questions and post photos before you consider cutting things... lots of previously healthy orchids have been killed by people cutting "suspect parts" based on YouTube videos. You can always cut after you have received some consensus from the experienced growers on the Board that it's necessary... but if you cut something you shouldn't, you can't put it back together.
Most valuable... observe over a period of time, and be patient. Orchids don't do anything fast.
Some other basic principles:
Orchids (with a very few exceptions) are light feeders. If they get less fertilizer than they need they may grow more slowly, but they will still be OK. Too much and you can kill them. Bloom boosters don't do anything... if you want less nitrogen, just use less fertilizer or none. Fertilizer is the least-important cultural factor, behind light, temperature, watering, air movement, media quality. Think of fertilizer as vitamins, not food... orchids, like all green plants, make their own food by photosynthesis. Fertilizer (in very small quantities) provides the minerals for cell growth, etc...and orchids grow slowly so need very little.
Orchids need air around their roots - when you water, water until it runs out of the pot (which also pulls air into the roots zone) Then let it dry somewhat before watering again, how long to wait depends on the need of the plant. Oncidiums want to stay wetter than Cattleyas. Phalaenopsis need to dry out but not bone-dry. Use smaller bark (or ssphagnum, etc.) for those that went to be wetter, larger bark, stones, LECA, etc for those that want to be drier.
There is a Sticky at the top of the Beginner Forum
The Phal abuse ends here. with many pages of good advice. Don't try to digest it all in one "read" ... but do read it.