I'm in a similar situation, and what improved my skills immeasurably and quite quickly was getting a set of rollers. I bought mine on eBay for 20 € for rainy day riding. The first time I tried them, I couldn't even balance properly without holding on to a door. Now i can balance, change gears, and reach for my water bottle. This has translated to a much more solid ride out on the road, whether it's no-handed, reaching for my water bottle or cornering.
As always, YMMV.
B