Here is a short list of things I’ve learned using stir plates in general and these stir plates specifically for several years now:

Use water first:

When you first try out your stir plate, give it a wet run with water. That way you can see and hear the stir bar center on the spin magnet and you’ll get an idea of what it should sound like at a decent RPM. It’s not uncommon for a particular stir plate/magnet combination to throw the stir bar at a particular RPM in the middle of the RPM range. The commercial stir plates I had over the years would throw a particular stir bar at a low RPM but would hang onto it at high-speed and the other would always throw plain bars right in the middle of the RPM range, but never ringed bars. The magnets I use work extremely well for this application, but because each is a little different, each stir plate is a little different. Playing with it with water will let you get to know your plate.

Faster isn’t better!

This stir plate is capable of spinning the bar much faster than is necessary and can throw the bar at higher speeds. The best RPM is one that keeps the yeast in suspension and creates a small dimple in the surface of the starter wort. Creating a deep whirlpool to the bottom of the flask just beats the yeast up unnecessarily and can cause the plate to throw the bar. Since the starter is constantly producing a heavy layer of CO2, you will not pull more oxygen into the starter without providing oxygen to the starter itself. The purpose of the stir plate is to keep the yeast in suspension and force the CO2 out to create a better growth environment.

Foil is better than an airlock:

When I first started making starters, I always used a 3-piece airlock on my flask and I sprayed down half my kitchen with Star San. There really is no reason to use anything other than clean, sanitized aluminum foil. This will at least allow a little gas exchange back into the flask and still prevent any airborne bacteria from getting it. I’ve been using this method for years and never had a contaminated batch.

Using a 2L to 5L flask:

When you place a 1L flask on the plate, the stir bar will probably center itself and grab the spin magnets. When you use a 2L flask, the stir bar may not center itself on the plate because of the increased diameter. Just slowly wave the flask over the plate and you’ll hear the stir bar grab the spin magnets. If you do the wet test mentioned above you'll see this happen.

Keep another magnet handy:

I learned this one the hard way after pitching several stir bars into my fermenters only to lose them later when I forgot and dumped them with the yeast. (They’re hell on your garbage disposal!) I make it a habit of keeping a magnet near the stir plate when I’m making a starter. Anytime the flask comes off the stir plate, I make it a point to ‘lock’ the stir bar to the flask with the magnet. That way, the bar is never dumped out with the starter and best of all I don’t even have to think about it anymore, it’s just part of my process! Having kids I discovered the Tot-Lok and I use that "key" for my spare magnet. it's great because it's plastic coated and reduces the risk of breaking or chipping my flask.