Sorry for the four posts in a row. Here are some strategies that may help. Keep in mind my thought above on the game's inconsistency. This might not work in every session, but in general it's a good way to get a decent score.
Rule #1. Split the Stix whenever you can. Each time you spilt them, your score multiplier goes up by a factor of 1. So after level 4, you should be earning 3x as many points as you were in level 1. The secondary benefit to splitting the Stix is that it's a quick and relatively easy (depending on the temperament of the Stix, at least) way to beat the level. The only problem with this is that sometimes the twin Stix absolutely refuse to split up, and you waste so much time waiting for them to put a little distance between each other that the sparks start to multiply and come after you. Your multiplier stays with you even after you die, until your game is over. But if you're not splitting the Stix, your score isn't going to be nearly as high as it could be.
Rule #2. You earn more points when you complete a box with the slow-draw option, or whatever it's called. You would think that this would be incredibly risky, and therefore not much use, since you move so much more slowly when holding down A or B. But here's the trick: At the beginning of the level, starting at the bottom of the playing field, build a thin, narrow "pillar" upward toward the top of the playing field. Use the standard draw speed when you're doing this, because it's safer, and if your pillar is thin enough then you really aren't wasting too much of a point potential. Also, do this with as many small boxes as you need to do so safely. Once your pillar is about 80% of the way to the top, sit at the top of your pillar and wait for the Stix to move away from you. Then, using the slow-draw method, draw a line connecting your pillar to the top of the playing field. The entire side of the playing field opposite from where the Stix is will fill in with the slow-draw texture, and you'll get some nice points. It doesn't make a huge difference at the start of the game, but when you've built up your point multiplier with multiple Stix splits, it's pretty significant.
Rule #3. You can use the same pillar method to split the Stix more easily, but you shouldn't build it up more than about 60% of the height of the playing field. If you build your pillar too high, the Stix won't want to move around it and you'll have trapped them on the same side of the playing field, giving you less room to navigate and therefore making it tougher to split them. You can also build a T-shaped pillar, either capital-T or lowercase-T, and navigate around the structure so that you don't have as far to go to reach the far side of the playing field when the Stix finally do decide to put a little distance between each other.
Rule #4. If you're using the pillar method, and your pillar is somewhat symmetrical, you can use it to avoid the sparks. Both sparks should cross more or less at the top of your pillar. Wait for them to get close, move out into the playing field a tiny bit, and as soon as they've crossed and begun to head away from you, move back to your pillar to complete your tiny box. Of course, this only works if the Stix isn't breathing down your neck, but if you can pull it off, you won't have to think about the sparks again for another 25 seconds or so.
Rule #5. Let's say you have a nice box in the corner of the playing field. You can actually build a second box that's perfectly kitty-corner to the first one, so that you can travel along either edge of the box. This is a little loophole that would probably make it easier to avoid the sparks if you want to play around with it. Usually I'm too busy getting kicked around by the Stix to make much use of this, but I'm aware that it exists.
That's all for now. Hopefully you can use this to boost your scores a bit. The killer part is that even with these tricks, the game is still incredibly difficult. Good luck.