Here some options that don't involve vandalizing your face.
1. Ponytail holders
Stop Your Glasses from Slipping Off Your Face with Ponytail Holders
2. Ear Hook
Anti-slip Holder for Glasses
3. Nerd Wax
The Original Glasses Wax
This sounds like a joke, but I found it works well for quite some time before needing to pull my glasses up by hand. I learned to pull my glasses up with my ears! Doing that taught me how to wiggle my ears and get children to laugh, so that might be an additional reason to learn. Dunno how I started, but I was being frustrated and started not being ...
I use shampoo to clean my glasses. While showering, lather your hair with shampoo. Use the lather with rubbing motion over the entire surface of the lenses. Rinse with clear water. Dry the lenses with cloths that will not damage the lenses (I use a microfiber drying cloth).
The reason this works well is that shampoo is designed to break up body and hair ...
I've been an eyeglass wearer and headset (as well as hearing protection) user for about thirty years. Here's what I've learned:
Everything depends on the thickness of the arms of your glasses. Thus if you have another set of glasses with thinner frames, you might want to wear those with the headset. Otherwise, of course, this point isn't ...
I found this Lifehacker article with a good answer.
Pinhole Reading Glasses
Put your index finger, middle finger, and thumb into a circle and leave a small hole in the middle (the three fingers of the same hand allow a tiny triangular opening which is held less than one inch from the eye). Bring the hole to your eye and look through.
How this works
There's no need for extra gadgets or body mods, you simply need to make the glasses a tighter fit.
Tighten the screws fixing the arms to the main part of the glasses.
Carefully bend the arms so that fit more tightly to your head and, in particular, so the hooks on the end fit tightly behind your ears.
There are a couple ways to go about a clip-on solution that might be appealing to people not comfortable wearing contacts or glasses over glasses.
There is a detailed post about creating 3D Clips For Prescription Glasses that addresses this precise issue.
The simplified version is: use a set of clip-on sunglasses, harvest the lenses from a ...
The AOA recommends washing glasses every morning, paying special
attention to the frames and earpieces, where hair product and makeup
tend to rub off. Whatever you do, don't use the most handy form of
water to clean your lenses. "Some people use spit, but don't," urges
Dr. Geist. Though dirty glasses won't cause an eye infection, ...
Qick and easy
Hold the glasses in front of a white paper or wall until the sun (or a far away window) is in focus. Measure the distance (in metre) between the glasses and the paper. Divide 1 by this value to obtain the glasses dioptre.
Physics behind this
Reading glasses are similar to a thin looking glass. The same optical rules apply to them:
You missed a loop. Two, in fact, on each end of the glasses holder cord.
Bend the elastic loop in half and put one arm of the glasses through both loops of the "8" formed by the bent loop. For stability, put the neck loop end closest to the frame hinge. The second loop nearer the ear hook is a stabilizer to hold the position on the arm you choose.
You need to crank up your observing dramatically. On your way to work/school/shopping, at work/school/shopping, in the stock photos that you see online and in articles, in any paper media you consume, in TV ads for floor cleaners or prescription meds or beer, look, really look at the people. Ask yourself:
does that person look roughly within 10 years of my ...
You can use cyanoacrylate glue to fit the "glass" back together. The bond will probably not be as strong as the original if it is glass.
Follow the instructions on the glue bottle for the best results.
A lot of glass lens are made from some type of plastic material. Glues can damage the lens in those cases.
The only good repair is to replace the lenses.
Try these methods:
Usually there is a screw at the corner of the glasses that keeps the lens tight in place, over time or by excessing movement that screw may loosen. Take some small screwdrivers, flat head or other and tighten that screw. Keep that screw tightened for better results, and carry some screwdrivers with you so that you can ...
In a hurry: Run them under the hot-water tap, then shake dry.
More thorough: Run under warm water then massage with a dab of dish liquid (not soap) and rinse well. Polish with a clean cotton tea towel, i.e. one fresh from the cupboard, not one hanging around in the kitchen.
My Dad's method: As above, but with clean boxer shorts, fresh from the underwear ...
From cycling experience (read: significant breathing activity and wind. And once standing at traffic lights, the wind which usually blows away the wet breath is gone and glasses tend to fog immediately). I didn't find a way to keep the nose covered. i.e. use a ski mask designed to cover mouth and nose which is a bit generous in the size of the eye whole and ...
May sound strange but a little bit of spit on the inside of you glasses will stop them from fogging, divers use this to keep there masks from fogging. Also there are different products like this spray. But spit works just fine.
If you have other glasses, this may be your solution: Remove the screws from both temples and set aside. Using the hinge on the glasses as an anchor, replace temples with elastic cord cut-to-size to wrap around your head. I used a croaky cord attached with thread through each temple hinge. It works great and I am very comfortable.
I would say try to dress more practical rather than professional to appear your age. I'm in the same demographic as you, and I've found that just swapping to professional attire that doesn't suit your environment comes across as pretending to be a grown up. Swap out faded or torn jeans for jeans in good condition with a slightly higher waist(won't ride down ...
There are many options that you can do, but none of them are preferable.
You can just wear the 3D glasses over your regular glasses, but may be uncomfortable.
Wear contacts. This may not be a option for many, but it will be a lot more comfortable.
Wear the 3D glasses by themselves. This is a good option but you might not be able to see.
Avoid 3D movies. If ...
If you happen to be a bit of a welder - you can use shade 14 welder's glass which is basically a neutral density filter which will be enough protection for your eyes from the Sun's glare. This sort of material is usually available from some hardware stores and it can always be obtained online if not (I would add a link to somewhere you could get it but I ...
The toothpaste method, as mentioned in your original question, may have to be repeated several times, especially if your glasses had an anti-scratch coating to begin with. 
If your plastic lenses have a coating (like anti-reflective coating) on them, then chances are it's just the coating that's scratched. A "thick paste with baking soda and water" may ...
You can mimic the method they use at eye glasses stores buy using a hair blower/dryer.
Use the Dryer on LOW heat, and take your time, slowly bending it into your preferred shape.
The key to this is to do it very slowly to prevent breaking them (cheap or expensive, they run the risk of breaking when you mold them if you don't take your time, so take your ...
When I was a kid my stepfather (blind as a bat and very particular about his glasses frames) would gently heat them by holding over the stove, then gently bend them into desired shape. It was always very effective.
Even as now the solar eclipse is over I want to post an answer :)
Please note, that it is extreamly dangerous to look into the sun directly, as it (the UV light) may damage your eyes irreparably.
It is recommended by all officials to NOT! use smoked glass or even welders glass (under #14), rescue blankets, CDs, X-rays or anything improvised. The risk of ...