I used to be pretty horrible at building houses but now I just love it. I think I've gotten pretty good at it. What has helped me recently to get better at it is the 3D model floor plans. I follow the floor plan by placing the furniture first as it's shown on the model - then build the house around it. Sometimes you have to delete the objects as you know how finicky the game can be. And you also have to make adjustments because you don't need the extra space shown on floor plans for closets and water heaters, etc.
Most houses are pretty "square" too. That doesn't matter as once you decorate and have nice windows, doors, shutters and a few plants and trees and maybe a porch - it all looks pretty nice! (Helps to make your roof not look as square as the house).
I can't build very large houses either - not yet, anyway. I think my favorite size lot is 20x20.
This roofing tutorial and practice helped me alot too - http://getsimplyruthless.blogspot.com/2013/11/victorians-101-getting-started-building.html
https://64.media.tumblr.com/2206d1150a706bd143805a95f6e6cf8c/9e0c880d54a692a5-c9/s500x750/14f878b18403864a656a1879fd29fae4a6f00200.jpg
https://64.media.tumblr.com/3b1521cda6e6e82d5f077830c34c8dce/9e0c880d54a692a5-25/s500x750/67f952851f821e41a391c7dfae028abac9d3b197.jpg
https://64.media.tumblr.com/39e4c5edc68580ea59c20466be6ab5c7/9e0c880d54a692a5-0b/s1280x1920/a430faaa4d3f00c5bc3a6667f530c090f0991fb4.jpg
https://64.media.tumblr.com/527f4750b702be897eddc5244ef6929c/9e0c880d54a692a5-c5/s1280x1920/e5a86ae150bb85bd5b74a9556cc2d05a4e79ddd2.jpg
https://64.media.tumblr.com/e1536358b0d58bdde34cbeb24562620c/9e0c880d54a692a5-41/s1280x1920/c86d7d3e7a12870536af5b7a9bc2a7b8e9c1c638.jpg
P.S. This house is available to download - https://katyfernlily.tumblr.com/
