When did you start EC? Wasn't clear in your post....it makes a difference as to what I should suggest. :o)
Our 12 mo old is extremely active but we've been ECing since birth so we have some communication history behind us. In any case, here are some thoughts on ECing an active toddler:
1. If you have an outdoor area, get or make some split crotch pants out of regular pants with a hole cut out, use a pattern (there's one listed on the Resources section of my site), or cut the crotch out of baby tights; or leave him bottomless. Or if you have hardwood floors, try it out one day when you won't mind some misses! Then....
2. When you see him peeing, state matter-of-factly "you're going peepee on the ground." You can make reflections that include your own emotions, but do not praise or scold...just be neutral and reflective. If you're indoors, say "peepee goes in the bathroom" and take him with you. Or tell him, "let's peepee outdoors next time" if that's an option.
3. Try various diapering or trainers or underwear options....some babies signal ONLY in a diaper, ONLY in undies, ONLY naked...it really depends. You might discover a signal if he wants you to help him get out of whatever he's wearing to not soil himself. (If you started after 5 or 6 months old, he may never signal...but I've definitely been wrong before!)
4. Try diapering him in just a prefold folded in half, held in place by a diaper belt (they are very inexpensive). That way, you'll know immediately when he's wet and can make a reflective statement and change him right away.
5. Communicate a bunch, but don't hover. Reflect, reflect, reflect.
6. Do diaper-free time often and let him experience "cause & effect"....even if you NEVER catch anything for quite some time, know that the process IS working!! If he has been diapered full-time beyond the sensitivity period (0-4 months), then it will take some time to unlearn all of that. Be patient. :)
7. Potty books and games ARE helpful...but never force your baby to sit on the mini potty. Try a potty reducer too. Have an open-door bathroom policy and eventually he'll WANT to do what you guys do!
I hope some of this will help you.....let me know if you have any questions about what I've shared... <3