There are a number of ways to change linestyles and it is important to be familiar with all of them. It took me some time to track down how to change different linestyles so I thought I'd dedicate a post to linestyles.
Linestyles for Model Objects like walls, doors, roofs, topography and other families are located under Settings... Object Styles. Here you can set the Color, Pattern, and Material of any family's linestyle. You can also change the lineweight of the family's Cut and Projection lines. Cut lines are lines that your plans and sections are cutting through. Projection lines are lines BEYOND or lines that lie beyond the cutting plane. You will also find linestyles for Annotations and Imported Objects here. These changes will affect linestyles GLOBALLY. If you want to change a linestyle in just one particular view you will have to go to View... Visibility/Graphics or use the Linework Tool.
Let's say you're drafting with Model Lines and Detail Lines. At the moment these linestyles are located under Settings... Line styles... but there is talk of moving them in with the Object Styles.
Now let's say that you've started a new family using one of the family templates but you can't find the linestyle that you want (say a dashed line for instance). To create a new linestyle go to Settings... Objects Styles... and add a Subcategory. Construct your family and import it into your project. You now have the power to turn on/off your new linestyle under View... Visibility/Graphics.
Now let's say you've constructed a model of your project but there are stray lines that you can't seem to get rid of. You can use the Linework Tool (LW) to set any visible line... invisible. Another great use for the Linework Tool is if you wanted to show the line of a balcony above in your plan view. Goto the view's properties and change the Underlay from None to 2nd Floor for instance. Now use the linework tool on the edge of the balcony above and turn off the underlay. You'll notice that the new linework remains. The linework tool is view specific so any changes you make are only going to be visible in the current view.
Now let's say you just want to OVERRIDE the linework in one specific view. For this we go to View... Visibility/Graphics (or VG for short). Here you can override Line Weight, Line Color, Line Pattern and we can Halftone an entire or part of any category. Halftone comes in handy when you've imported a DWG that you want to show in greyscale.
Drafting and model patterns use lineweight 1 end of story. If you want patterns with heavier lineweights you'll have to use filled regions.
Now lets say you have a floor, wall, or ceiling with many layers in their construction (finish, sheathing, framing, etc) and you want to change the lineweight, color, or pattern of one of the layers. If you go to View... Visibility/Graphics... and check the Cut Line Styles box you can now edit Host Layer Line Styles.
I think that pretty much covers linestyles for this post and I hope you've found it helpful.