I have just a quick answer to this.....Are You riding with boots that have even slightly slippery soles? If this is the case then CHANGE THEM for ones with totally soft Gel Soles, you will grip the surface better no matter what kind of surface it is.....
STOP thinking about making mistakes and start by leaning the bike as far as you can WITHOUT the engine running in your own driveway, see how far you can lean it without it taking you down, if it aint far then you have the wrong boots on...you "Should" be able to lean a bike around 40 degrees from upright and hold its weight easy, and take it back to upright, do this on both sides and see if its the same amount each side, once you know how far you can lean it-once you have very soft soled boots on-once you can take your gearchange foot off and put it to the floor while moving at slow speed-then you will get the hang of all of it...
Keep the brake foot on the peg until you have stopped and lean very slightly toward the other side, but just very slightly, you will have the balance to keep it right ways up ok? Practice without the engine somewhere the bike aint going to get damaged-even put a load of chair cushions down where the bike would fall to.....I reckon maybe you are not sure just how far you can tilt the bike without it going over...FIND OUT...and THEN go back out on the road and you WILL feel a load safer putting a foot down, and then both feet ok? Of This I Am Sure.....
See, and thats the SHORTER, QUICKER Version of what I wanted to say.....lol.....
The reason I said all that above is that I have a friend who now rides a rather heavier Harley than mine, she also rides a rather large VN Kwak, and she is just a slight built just over 5 feet tall...she used to have this trouble for around a year after she started riding, and that was on an NC400...
Then we saw what she was wearing on her feet, we made her put soft soles on and it gave her enough of a boost to try what I said above about engine off and see how far you can lean it.....Do it safely, have someone standing by your side so they can stop it falling, but just do it without going anywhere first.....ok?
Hope this helps in some small way.....
I have always said that if you cant pick your own bike off the floor then its a bike thats too heavy for you....now just because thats the principal I go by dont mean its right for anyone else...
In case any of you didn't know.....
I am technically 3 limb disabled, I still ride my Harley as often as I can, I still ride it like I stole it! But even with both my arms limited and my left leg limited I can still pick my Harley off its side.....
First thing I did when I first got it all set-up to ride how I wanted it was to have help lowering it onto chair cushions...then after a struggle I picked the damn thing up on my own.....only then did I know it was mine!!!
I now have close to 40k on it, but please bear in mind, I have 2 bikes and 4 trikes and a couple of other vehicles.....for me to do the average miles of 15,000 miles a year it gets split between all those vehicles, so even though they aint done the miles that some do they do their share every year...
I have all manner of boots.....my favourite boots to ride in are a genuine pair of German Paratroop boots made in 1941 and left on Guernsey when the Germans retreated and left everything behind.....I paid £20 ($32 approx) for them and they were only just broke in when I got them...they fit me perfect, whoever he was he had the same odd feet that I have as they fit me like a glove, I have had them 6 years now and they stilll shine up the same ..... They have very good and very rugged grip on them.....