Hi @SweetieBelle!
Sorry for the delay in responding- I was away from my computer today. I want to second what @greeneyedgirl107 said about Paula Begoun. I think she has great advice (and some great products). If you can't get her book, she has updated articles and info on her website that are just as helpful. If you're curious about skincare products, I think her Beautypedia reviews are a good starting point, as was already suggested. As with anything, I don't agree with everything she says, but her book years ago started me down a path to better skin. I also really like the articles on Dr. Cynthia Bailey's website. She's a dermatologist out of California and she has rosacea so she talks a lot about sensitive skin.
I think there's quite a lot of good antioxidant products out there and it might be a matter of trial and error to find what works for you. I should specify that my skin is truly very sensitive and picky (I have rosacea), so just because something doesn't work for me doesn't mean it's not a good product.
For Vitamin C, most dermatologists love Skinceuticals CE Ferulic, which is a great (though expensive) product. I've also used Drunk Elephant's Vitamin C (available at Sephora, but also available elsewhere for a discount sometimes- check Dermstore and B-glowing for coupons). Neither one of these really agreed with my skin, but I think they are both well-formulated products that work for many. I've also heard great things about Mad Hippie's Vitamin C serum, but I haven't used it before. It's more affordable as well. My personal Vitamin C of choice is from SkinMedica- it's slightly weaker than Skinceuticals, Drunk Elephant, etc. and comes in a silicone base (as opposed to a more watery format like the others I mentioned). I can't use a C serum every single day or if my skin is acting up, but I think I might be in the minority on this front. There's a bunch of other C serums, these are just the ones I know best!
As for green tea, it's really my HG antioxidant. It's great for people who can't tolerate Vitamin C. My skin loves it and it's always calming. I use it at least once a day, if not twice. My favorite, far and away, is Replenix's Power of Three cream, which contains green tea, caffeine, and resveratrol, all potent antioxidants. They also make a serum formulation with similar ingredients, but my favorite is the cream (personal preference). I can't say I've tested a bunch of other green tea products because Replenix's cream just worked for me so I haven't explored further. I get the Replenix from Skincarerx (again, because of discounts), but there are other places to get it (just make sure it's authorized- I once bought it on Amazon and it was a fake!). I've also bought products on Ariva's website with discount codes and had good success.
Paula's Choice makes some good products and they have a great return policy, so they might be a good place to try different ingredients/types of products and see what works for you. I've used her antioxidant serums and her retinol serum with great success in the past. I've just found some other products that better work for me now.
In any case, here's a brief summation of my routine. Again, I've got rosacea, so I use prescription creams for that, and, admittedly, my routine can seem a little intense because I am a skincare obsessive who has had a lot of skin issues in the past. My routine fluctuates based on my skin's finicky needs too.
For in-office dermatologist procedures, I've tried many, many lasers and light-based therapies. What will work for you is really dependent on your individual skin because they all do different things. I think if you go this route, you'll have to talk to a dermatologist who can really assess your needs. I also get fillers about once a year and have for 11 years (genetically, I have less volume in the tear trough area, so this isn't as much for aging). I also occasionally get neurotoxins in the elevens and in my forehead (I get a tiny amount to avoid looking frozen). My neurotoxin of choice is Dysport, but I've also tried Botox and Xeomin. This is really a matter of personal preference- they all have different benefits and work differently for different people. I probably get a touch-up every 4-5 months and I think it's helped as a preventive for my elevens.
At home, I do LED treatments (red light), which is mostly for my rosacea, but I do think it helps a bit with signs of aging. I started doing these treatments at a spa and realized it was more cost-effective to buy a device and do it at home. As for products, here's my current list (I rotate these based on my needs):
Prescriptions (for rosacea): Soolantra (night) and Elidel (whenever I need it)
Face Wash: Paula's Choice (PC) Gentle Touch Makeup Remover, Bobbi Brown Instant Long-Wear Makeup Makeup Remover, Clinique "Take the Day Off" cleansing balm, PC Resist Optimal Results Hydrating Cleanser, Cerave Hydrating Cleanser
Face Toner: PC Skin Recovery Enriched Calming Toner (I love this so much!), PC Resist Advanced Replenishing Toner
Sunscreen: TIZO Ultra Zinc (this is a 20 percent zinc sunscreen, which I love because my skin doesn't handle chemical sunscreens)
Main Antioxidants: Replenix Power of Three Cream (love, love, love) and SkinMedica Vitamin C+E Complex
Hydrators/Moisture (this can vary based on the season, but these are my summer products): SkinMedica Hydrating Complex or SkinMedica HA5 Rejuvenating Hydrator (my skin is dry and does well with Hyaluronic Acid), Pure Marula Oil (Drunk Elephant got me started on this, but I think Acure Organics Marula is just as good, for a fraction of the price)
Treatments: SkinMedica TNS Essential Serum or Recovery Complex (This contains growth factors and can be controversial-- it works for me, but I know others are more wary about growth factors.), SkinMedica TNS eye repair (it's awesome, but I hate that it's in a jar), SkinMedica Retinol .25 or .5 or Differin (I alternate days and don't always use every single day)
Exfoliants: PC Skin Perfecting 8% AHA Gel or SkinMedica GlyPro Antioxidant Serum, dabble with Drunk Elephant's T.L.C. Night Serum (I think this is good, but my skin doesn't love BHA and this contains BHA along with the AHA)-- I use these once or twice a week
Whew! I think that's it. I know this might seem a little crazy or intense, but I don't use all of this at the same time and I do rotate. But don't feel overwhelmed-- there are people with much simpler routines who do very well. Since you're working on building a routine, my advice would be to start with basics: a gentle cleanser (this isn't where you need to spend your money since it doesn't stay on the skin long), a good retinol that your skin tolerates, antioxidants in some (or multiple!) forms, an exfoliant (AHA or BHA, or both- whatever your skin likes), and moisturizer of some sort (if you're not getting moisture from your other products). It seems you have a sunscreen you like so stick with if it works! And, if the Argan oil is working for you, keep at it too.
I'd also advise trying things little by little if you're at all concerned about reactivity so you know what works for you and doesn't work. I've made the mistake of trying multiple new things at once and then had a reaction and didn't know what was causing it. Also, and I think you already know this since you were careful to cut back on the Good Genes when you had irritation, it's important to start slow with retinol or AHA/BHA and not overwhelm your skin. You don't want to strip your skin's barrier, which just makes lines look worse (been there too).
Maybe this is silly too, but have fun with your skincare routine (perhaps I'm weird, but I do)! Don't get discouraged if something doesn't work for you- there's so many products out there now, you will find products that work, I promise. If I can find stuff for my picky sensitive skin, you can too!