First well start with core basics.
Make sure the string is over the yoyo axle before you throw.
Make sure your hand is facing “fingers away from your body” to catch it. If your right handed, throw breakaway to the right, make sure your fingers are pointing to the right as your catching it to avoid the string ending up under the axle. (my co worker had this problem and it took me a while to figure out exactly what he was doing wrong.)
If you are missing the string for your trapeze, when you miss, FREEZE. now look at where the strings are at. If your yoyo is on the inside (closer to your body) of the trapeze line, move your throw hand closer to your body and try to flip it around again. If you miss, FREEZE. look at the strings. Is your yoyo on the outside (farther away from your body) of the trapeze string? move your throw hand a little bit back away from you. Your misses are telling you exactly whats going wrong if you can stop and observe. This is most apparent while learning the breakaway and trapeze.
(just watched the video you linked)
Just keep practicing the throw. Try not to have your wrist slanted when you release. Just like with bowling or frisbee, your angle or degree you have during release will be held by the gyro forces at work. So try to keep it on plane by being mindful of the release.