First off, welcome to YoYoExpert! Just a suggestion, this topic is more appropriate for the “Yo-Yo Tricks” section. The “Looking for Help/Recommendation” is more for help with picking out yo-yos.
Anyway, here are some tips:
You’re gonna have to pay close attention to the gap of the yo-yo during those tricks; keep the strings parallel to the sides of the yo-yo as much as possible. Straight breakaways are very important.
Another thing to remember: yo-yos tend to tilt more when they’re about to run out of spin. So having a strong throw can prevent tilting.
Lastly, in Dr. Strange, if you pull the strings apart too much then the yo-yo will tilt. Just pull them apart enough to keep the strings straight and the yo-yo shouldn’t tilt.
… To sort of sum up what jayvee said, just try to avoid letting the string touch the inside of the gap; that slows the yoyo down ALOT which causes the yoyo to tilt because it is slowing down.
Also watch your throw. If it tilts to one side adjust it on the next throw by twisting your wrist slightly in the opposite direction when you throw. Adjust as needed until it’s straight. Keep working at it and it will come more natural and you’ll develop the right feel for it.