There are several alternatives to using a chalk line that you can try. Some of the things you may have already around the house.
A chalk line is used to get a straight line either horizontally or vertically. A chalk line can be messy, and must be refilled regularly. If you do not understand how it works, then it can also be misused.
One of the best alternatives for a chalk line is a laser line or laser level. This tool isn't expensive and if you do a lot of do it yourself projects the investment will be worth it. Most have a suction cup so you can firmly attach it to either a vertical or horizontal surface. Then all you need to do is turn it on, and it will balance and level itself and a red laser light will show along the straight area. You can use chalk, paint or a pencil to mark along these lines.
Another alternative, and a very inexpensive one, is a weight attached to a light weight string. Just drop the string and the weight will go to true plumb or straight. Of course this will only work on a vertical surface. You can mark along this line for a straight edge for carpentry or wallpapering.