I was reading about the Quakers the other day...
Some Quakers, practice 'plain dress', there are other groups too who do this in varying degrees, the most famous being the Amish who have a sort of uniform.
But even without very 'distinctive' plain clothing, the Quakers were talking about just wearing clothes without branding, or not wearing a tie... or that sort of thing... Just dressing modestly.
✝️So, I'm wondering what opinions might be about more generally and how Christians feel about these matters?
Do you follow Bible teachings about modesty and how you dress? Jewelry? Make-up? Etc etc?
The Bible does not tell us what clothes to wear. Only that we ought to be modest and not try to emulate the other gender.
What is "modest" varies greatly depending on era and culture. And even within one era and one country, it will vary still between denominations and sub-cultures.
So you won't get any one, blanket answer on "what is modest, acceptable clothing for Christians".
This is a verse often cited for being "against" women wearing anything flashy:
1 Peter 3:3 Your beauty should not come from outward adornment, such as elaborate hairstyles and the wearing of gold jewelry or fine clothes. But note that it doesn't say "Don't wear these things", it says "don't let your beauty come from them". Immediately following is:
4 Rather, it should be that of your inner self, the unfading beauty of a gentle and quiet spirit, which is of great worth in God’s sight. 5 For this is the way the holy women of the past who put their hope in God used to adorn themselves. Again, notice that it doesn't say "Don't wear these things", but rather that a woman should let her beauty reside within more than without. That the beauty of her spirit is far more valuable to God than the beauty of her clothes or hair. I do think it's a fine and difficult line for many women to walk. Placing a lot of time and effort into making yourself up is likely to leave you admiring your appearance moreso than if you didn't place a high priority on such things. And self-admiration is a very slippery slope. Not many people (male OR female) are good at restricting themselves to a modest "I look nice today!" and then not giving their appearance another thought, but it is possible. So, the risk of wrongdoing doesn't lie in the hairstyle or the earrings or the makeup, but in the heart of the one donning them.
For me personally, I prefer clothes that don't show cleavage or go too high above the knee, and nothing very tight or form-fitting. I don't wear makeup beyond a quick brush of mascara to make my invisible eyelashes visible

I don't style my hair. I enjoy earrings, I find it's a lot of fun to pick out a pair each morning. I don't wear any other jewelry most of the time. I rarely stop and think about how I look during the day. If someone compliments my earrings, 99% of the time I have to stop and reach up and touch them to remember what I put on lol. I find it quite liberating to simply not think about my clothes or hair or makeup as I go about my day. It frees my mind to do other things.