I was taught many years ago that
- A cut keeps you in the room
- A dissolve takes you down the hall or next door
- A dip to black takes you anywhere else.
IOW, the longer the transition, the more you give an impression of the passage of time or that the location has changed significantly.
As mentioned, the texture mapped warps, shreds, twists, spheres, etc really need to be avoided unless they fit the mood or have a really good reason to be used. Less is more.
Two other techniques that can really add some polish to a project are the so-called "J Cut" and the "L Cut." In a J Cut, you make a change in the video preceding the next change in audio and in an L Cut, the video changes after the preceding audio edit. Watch for scenes in shows or movies where two people are having a discussion and see if you can find where they use these edits. They're especially useful when you need to get to Character B's reaction before Character A has actually finished their line of dialogue. These are almost universally done with cuts for edits.