I paint quite a bit of glassware including wine glasses & bottles. I've done one stroke flowers for the most part but recently learned a new techniques that give me a much wider range. I'm particularly fond of my wine diva.
I appreciate your enthusiastic responses & thought I'd mention a few more things.
Since I began painting bottles, I've come up with several uses for them other than just sitting on a shelf looking attractive. Not being a great connoisseur, most of my wine comes from a box. When I go to the clubhouse for social hour (or any other place where I take wine) I fill one of my painted bottles---always guaranteed to attract attention.
They also make lovely oil lamps. Kits are available but my resourceful husband discovered that by drilling a hole thru a brass cabinet knob, we can roll up the end a long wick, twist it into the hole & set the knob on top of the bottle. Note the tall flat bottle with the pale aqua flowers.
Wine cooler & beer bottles are great too. When I want to remember someone but don't want to spend a lot of money on a gift, I've found that a beer bottle will hold nearly a full bag of jelly beans or M&Ms. There are just enough M&Ms left over to treat yourself while you cap the bottle & trim the top with ribbon & beads.
Flow restrictors are available at liquor stores so some of the smaller bottles can be used for bath oil, dipping & olive oil, or dish detergent.
I don't teach one stroke painting but can give a few hints on painting the other designs.
For most of them, I captured line drawings from free clip art sites, sized them as needed & printed them. I cut around the pattern, laid it printed side down on the table & moistened the backside with a damp paper towel. After dampening the INSIDE of the glass, I pressed the pattern to the moist area. I found that a rubber spatula sometimes helps to press the pattern in place. The moisture will help it stick to the glass long enough to paint the outline of the design on the outside of the glass. I replace the pattern with a folded paper towel before I paint the details in freehand.
I use enamel paints & pens for glass---usually FolkArt brand altho there are others. For durability, I bake the finish on. Put the glass in a cold oven & set it for 350 degrees. When it reaches temperature, time it for 30 Minutes. Turn the oven off & allow it to cool completely before opening the oven & removing the glass. Most paint companies say they're dishwasher safe but I hand wash them to be sure.