UPDATE: Due to the recent patch, some of these building tips no longer work correctly.
This video features a collection of 50 tips for building settlements in fallout 4. You can easily skip straight to what you're looking for by selecting the links below.
00:55 01.) Local Leader Perk
01:09 02.) Force Foundations Through Ground
01:19 03.) Water Purifiers on Land
01:37 04.) Stacking Foundations Vertically
01:48 05.) Snapping Difficult Objects
02:02 06.) Placing Decor
02:16 07.) Performance Issues
02:36 08.) Problems when placing Doors
02:48 09.) Stacking Floors Vertically
03:16 10.) Building Steps
04:03 11.) Forcing Foundations through Others
04:15 12.) Floating Floors Drop Straight Down
04:47 13.) Precise Rotation
05:00 14.) Snapping Prefabs
05:14 15.) Stacking Objects inside One Another
05:26 16.) Generator Comparison
05:48 17.) Lights on Objects
06:12 18.) Fixing Lights
06:32 19.) Largest Settlements
06:57 20.) Settlement Starting Sizes
07:17 21.) Keep Terminals Separated
07:41 22.) Stacking Delay Switches
08:09 23.) Power Counters
08:26 24.) Fast Travel Welcome Mats
08:39 25.) Rocket Turrets are Dangerous
08:50 26.) Moving Objects without Moving
09:03 27.) Moving Groups of Objects
09:22 28.) Making False Floors
10:27 29.) Indenting Walls
11:12 30.) Rotating on different Axis
11:25 31.) Moving over over a 1/2 step
11:49 32.) Rug & Mats Trick
12:11 33.) TV's in Walls
12:37 34.) Windows
12:59 35.) Ambient Lights for Windows
12:25 36.) Clearing out Crops
13:46 37.) Legendary Freefall Armor
14:27 38.) Making Caps $$$
15:11 39.) Materials (Wood, Concrete, Steel)
16:03 40.) Replenish Vendor Stock
16:44 41.) Size Limit Glitch
17:29 42.) Objects vs. Size Limits
17:52 43.) Unlimited Light Power
18:11 44.) Connectors on Mats
18:42 45.) Building Curves
20:09 46.) Hiding Power
20:22 47.) Lights in Walls
20:40 48.) Using Wires as Aesthetics
20:58 49.) Wires no longer require Copper
21:14 50.) Magazines to unlock More Settlement Options