1. Giving up too soon!
Seriously, most people fall at the first hurdle. And I was nearly one of them. I tried a couple of times to make a layout in Photoshop elements many years ago but each time gave up because I just couldn't work out what to do.
Then I was stuck for several weeks in a serviced apartment with a laptop, a napping toddler and no paper scrapbooking supplies. I had a "step by step first layout" guide from a magazine and once I had followed that I was away.
Luckily now there are lots of great tutorials online.
Once you have made a few layouts it gets quicker and easier, and after a while it becomes automatic and just FUN. There is a reason why digital scrapbookers will always tell you it is addictive. But don't be discouraged if at first it seems difficult and just plain hard work. And you can always ask for help at the Lilypad forum.
2. Distorting the proportions of photos or other page elements .. which is very easy to do but also easy to avoid.
You want a photo to fit into a certain space so you resize it, and it looks OK .. but to a seasoned eye the slightly scrunched proportions are clear.
The easy fix to resizing photos and other elements in Photoshop is to always hold down the shift key when dragging on the handles on the edges of the photo.
3. Not taking time with shadows
Shadows are tricky. If they are done well most people won't even notice them. Done badly and they jump out at you.
Common newbie digital scrapbooking mistakes include not using shadows at all, or using overly large and obvious shadows.
Shadows should be different for different elements. Thicker elements and those on top of other elements cast a bigger shadow. You can even have fun bending shadows to create a lifted effect.
And it is very rare that text looks good with a shadow. (Though there is always the exception to the rule!!)
4. Speaking of text ... there are thousands upon thousands of free for personal use fonts available so there is no excuse for using boring fonts on a page. Typewriter fonts are great for journaling, and there are some wonderful handwritten fonts too. Pinterest is a good source of typography inspiration. And think about the size. Smaller is nearly always better, although make sure it will be easily readable once printed especially if you are going 8" x 8" or smaller.
5. Unrealistically sized or too large elements
Digital designers are considerate bunch. They generally provide the elements in a large size, as it is better to resize down than up to retain quality.
But that doesn't mean you have to use the elements in the size provided.
Think about the size of your printed page. If it is an 8" x 8" layout you don't want a inch long staple on it.
The key is to play about and have fun trying out different looks with the elements, not just plonking it down.
Sometimes a big element can make a page:
Sometimes middle-sized is just right:
Sometimes small says it all: