Hi Shellie! First of all, no matter what method of filling you use (condom, dripping from the top into the filler or syringe), do not eyeball the amount of e-liquid you're putting in, especially for the first time. Boge cartos are notoriously difficult to fill because they are rather tightly woven; sometimes a top looks slushy but the inside may still be dry. A standard (35 mm) cartomizer takes 1 ml of eliquid, or 25-30 drops, depending on the size of the dropper you're using. Do not use your cartomizer until you're sure that the filler has been thoroughly saturated.
Start vaping slowly--do not chain vape and do not vape at high wattages (6.5 watts is just about ideal for a carto). And then don't forget to top off your carto--1 ml of ejuice doesn't last very long and you don't want to vape your carto empty. Top off early and top off often. Carto tanks make using cartomizers easy--and you can always see how much juice you have left.
Once a carto tastes burnt, it is burnt. Refilling won't help--just grab another one and fill it properly: make sure you put enough eliquid and make sure that the filler is saturated throughout--use a large sewing needle to gently poke some holes in the filler if necessary. Having a syringe with an 18-gauge needle helps, because it lets you insert a right amount of juice slowly and directly into the filler, from the bottom up. But it's not absolutely necessary.
Good luck.