Dabbling with Oils

I've just discovered Bill Guffey's Challenge via Liz's blog, and seeing that I've registered for an oils workshop which is coming up soon - painting urban landscapes - I thought I'd get some practice and see a bit of Lisbon at the same time. I found a street name that I recognise -Rua Bartolomeu Dias - who left little stone crosses around our southern Cape coastline 500+ years ago when he discovered the sea-route to India.
I settled on No 102 Rua Bart Dias because it had a nice bougainvillea peeping over the wall (although I didn't get much of it in my painting - I have mostly road-surface in that!) and it would make me tackle perspective - not my forté.

I love painting in oils, but feel very uncertain about what I'm meant to be doing, with fats over leans and how to stop everything squidging together when you try to finish a painting in one sitting. My good, kind, thoughtful husband gave me a set of oil paints, brushes and a stack of huge canvases for my fortieth birthday, and a few smaller canvas boards to experiment on before starting on my large 'works'. The first ones that I did on the small boards were so enjoyable, I felt free to dab away without obsessing if I was doing it correctly... and they are still the ones I prefer over all the attempts at masterpieces I've done since.
This early arum lily painting spent time leaning against a wall that had a severe water leak down it and the canvas peeled away from the warped board. I hadn't left enough space around it to stretch it over another support, so its a bit wrecked - any suggestions on how to stretch it again? That white border is all the canvas I have to work with.

My very first oil painting is this one on the right... done when I was 11 or 12 years old, on lined exercise book paper with a paint-by-numbers set of little oil pans. We were living in a flat next to the railway line in Cape Town, and I had just read a book about Vincent van Gogh, and loved his Café Terrace by Night so much that I was inspired to do a version - sort of (note the rather tipsy-looking man's bell-bottoms - it was during the 60's!)
I had forgotten all about this - I don't remember giving it another thought - until my little sister (who would have been 9 or 10 at the time) presented it to me a few years ago. She had put it away safely, kept it through four family house moves, high school, art school (me) and drama school (her) and my moving up to Johannesburg, taken it with her to live in America, and on a visit back to SA, one very surprising middle-aged birthday, tucked it into a gardening book she gave me! It's the only art from my childhood that has survived the years - thank you Gillian!!!