Is it a top or bottom pour mold?
If its a top pour mold I pull the wick up slightly before the wax sets,or pour a small amount of wax then place the wick, it keeps the base in the candle so it doesn't twist as the wax sets.
If its bottom pour then fill the mold until its almost full as the bottom shrinks (Top of the mold )
top it off if you do it before the wax completely sets it will be seemless.
Thats what works for me.