Questions about shifting from a new road cyclist I recently purchased a used bike from my local co-op. I've ridden previously on fixed bikes with straight bars, but this bike is the first one I've owned where I have to shift and use drop handlebars. I've been practising for the last two weeks or so, but am still uncomfortable with this. I have two big questions

1) I am having a lot of trouble simply keeping my bike steady with one hand while trying to shift. I am quite confident riding one handed and even shifting with one hand on the part where the handle bars curve out on the top, but have no control over my bike if I try riding one handed from the hoods. Its almost impossible for me to shift (with down tube shifters) and have a hand on the brakes just in case. It seems impossible for me to ride on the hoods and not have the handlebars carry a lot of my weight. I'm considering brifters just because then I'd never have to take my hands off the handlebars, but that'd be almost as much as I paid for the bike.

2) I have read that you are not supposed to shift while under load, but what about no load? I guess this partially stems from the fact that I'm not really comfortable shifting from the hoods, but I really have a hard time shifting and keeping control while still pedalling. Also, when I do shift while still pedalling, my foot sometimes comes off the pedal. Is there any way to prevent this without clipless pedals?
Sounds like an issue with bike-fit. Try the following:


While on the bike and stationary, lean on the wall with elbow (of one arm). The other arm/hand reaches the hood, your body should be as close as possible to the normal riding position (on hood).
two feet on the pedal
Use your back muscle and gradually reduce the load on the hood. Is this possible?


If the answer is no, which is what I suspect, try:


invert the stem, if you have threadless headset. Keyword: 'stem threadless adjustment' for further details on the internet.
increase the (quill) stem height, if you have threaded headset. You often seen this type on older bicycle (1980s and older), which is likely to be your case. Keyword: 'quill stem adjustment' for further details on the internet.
change the seat angle: change the angle so that the seat prevent you from sliding forward
change the seat position: slide the seat forward and have a more up right riding position. However, your centre of mass also shifts forward and your body is more likely to slide forward. Thus there should be a balance between seat angle and seat position (and stem length/angle).