Don’t over do it
Otherwise you exhaust yourself. Keep it light, simple and clear and don’t over do it in the chest voice.
Mixing the chest voice to the head voice
See the voice as a whole chest voile, passaggio, head voice All mechanisms are present in all registers
Keep the balance
The voice is one entity Don’t separate the mechanisms. The voice should sound equal Low and high notes should sound equal Find balance and harmony
Make sure to watch these tutorials as well:
SINGING HIGH NOTES (4 things to remember)
Strengthen The Head Voice (Ranges & Registers Part 3)
Chest Voice, Head, Passaggio, Falsetto (Ranges & Registers PART 1)
Finding The Chest Voice (Ranges & Registers PART 2)