Welcome to VFX! Having a 3D artist background will definitely be an asset to you. The biggest difference will be the motion, timing and animation. VFX has a lot of crossover with traditional animation techniques to portray the feeling of power and anticipation. With VFX you are telling a story through your visuals. Look up the 12 principals of animation.
Your effect is a great start I do have a few suggestions if youre open to it…
First, what “story” are you trying to tell with this effect? Is it a magical spell? Is it a physical phenomenon? Does it just do frost damage or physical damage as well? How does it affect the environment? Once you establish these ideas it will be easier to build a coherent effect.
You have a lot of motion that sort of conflicts with each other. There are various expanding rings as well as the orbiting ice. Each element isn’t bad per say, but they don’t harmonize very well together.
The orbiting ice feels pretty disconnected. I see you have an ice ball in the middle that is growing. I think it would make more sense if the orbiting ice was not just circling the core ball, but also being attracted to it. That will give the feeling that the orbiting ice is being compacted into the core ice ball, causing it to grow. It would harmonize those elements together and “tell the story” of how the core ice ball is being created.
The timing on your elements seem very disconnected from each other. You have a very fast smoke ring at the start, then a medium speed ring on the ground and then a very slow expanding ring. The fast ring reads like something exploded, the medium speed ring feels like its supposed to be some after effect of that first explosion and the slow ring reads like some countdown timer to the detonation. One thing to remember, speed equals the feeling of power.
If this is a magical spell, perhaps a rune circle instead of the fast ring? Just have it spawn at full size instantly. If its more of a physical effect i would have the medium speed ring follow very closely behind the fast ring so the fast ring is sort of like a shockwave front caused by the medium circle expanding. I might also add a bit of a flash or glow at the very start to signify something being triggered that starts this whole process.
For the small ring, i wouldn’t use a ring at all, it tends to read a bit more on the gamey/ui side. You have a bit more leeway if its a magical rune but if its a physical thing the ring doesn’t really work. Personally i would use a frost decal that sort of grows outwards towards the medium ring, is if the ice ball in the middle is freezing the ground as it builds up. I would use alpha erosion for the growth instead of scaling up the sprite. I might also put a curve on the growth speed so it starts slow and accelerates near the end. Your current expansion looks like its linear which doesn’t feel very organic and doesn’t sell any anticipation or buildup.
After the explosion it sort of dissipates away with no lingering elements to let you know that something happened. There is no decal on the ground and everything fades out very fast. Perhaps some small snow flurries that are swirling/falling and some more snow on the ground? A spikey snow/blast decal would also sell the idea that something exploded.
The ice chunks decelerate very fast. If this is a powerful explosion they would eject quite far and bounce off the ground. They just stop dead as soon as they hit something which betrays the feeling of power from the explosion. They also tend to fade out very fast, i would let them come to a rest for a split second before scaling them down.
I have a strange technique i like to do when making effects that helps me establish the story and that is to imagine the sounds it would make. Sometimes i physically make sounds with my mouth. It can help you imagine the smaller details and establish the story of the effect. An example would be something like boom vs ka-boom. The ka-boom feels more dynamic, it feels like something collapsed or quickly detonated in that split instant before the main boom. You can use these sounds to help dial in the details. A sound for this effect could be something like this…
Fwoosh/Fwoom>Creak/Crack>Ppshhhh!>Tinkle
The first fwoosh is the initiation of the effect. It is displacing the ambient air/environment. The creak is more like a high frequency ice stress/cracking sound. Rising in frequency and pitch as it progresses. As if the ice is being compacted by great force and is straining/cracking under the pressure. The ppssshhh is the explosion, since this is ice its more of a high frequency shattering sound instead of a deep rumbling boom like an explosion. The tinkle is debris hitting the ground after.
It may feel weird to do, you might get some strange looks if youre doing this in an office but it can really help establish the story of the effect. 
Keep it up! Youre on your way to becoming a wizard! 
