One technique: If your bottom layer has completely hardened but has not pulled away from the sides of the mold, you can use a heat gun (if you have one - guess you could use a hair dryer)) and heat the top of the layer until its slightly melted, then add the next darker layer. They will usually blend. This doesn't work well when making layer from different colors, like white and red. However, if your first has pulled away from the sides of the mold, your second layer will run down over it. Another technique: Let the first layer set up until it has hardened on the top, but is still soft on the bottom (it takes a little practise to know whne to do this). Don't poke holes yet. Pour the next layer and then poke your holes like you would ordinarily do. This is the method I prefer, but sometimes have to resort to the first one when I let the candle. You may want to practise on smaller candles with no FO to save money. As previously said, your jump lines on the rest of the candle can be from the wax being too cold, pouring too slow, a cold mold. Hth.