lungimsam

I fell a few times when I first started.

1. You will learn quickly to remain leaning your weight on the foot that is on the ground during a stop.
If you lean towards the clipped in foot during a stop - over you will go.

2. Make sure you are CERTAIN you are good and clipped in before standing while pedalling. A foot slipping off the pedal during standing pedalling is bad news. Just stay seated when you start off and get good and clipped in while doing seated pedalling. Don't try to clip in real fast and then stand up to pedal through an intersection fast. I fell once doing that. Embarrassing and got scraped up.

3. I unclip the foot I intend to put on the ground at the stop during braking when coming to a stop. I leave the other foot clipped in during the stop and lean toward the foot on the ground.

4. I have learned that some pedals are easier to get in and out of than others. If your current pedals don't work great, try something else.

5. If your knees don't like the SPD's, get some free floating Speedplay clipless pedals for maximum foot rotational float so your feet can rotate more degrees when clipped in. Your knees will be happy then. I don't like SPD's because they don't allow much rotation of the feet when clipped in, and the knees hurt. And you can't always adjust the cleats far enough for the rotation you need.

You will get it. Just takes time. And just remember to never lean your weight towards the clipped in foot when you are at a stop, and always be sure that you are clipped in well before doing any standing pedalling.

PS- it is tempting, but dangerous, to look down at your pedal while getting clipped in. Don't do it. Clip in by feel. Go slow and watch the road when you are riding, and keep at it with the foot until you get it clipped in.