One thing I learned from the editing service has always stuck with me. They circled something and wrote "1+1=2". Only the equal sign had a big slash through it, to show 1+1 didn't equal 2. It meant I was just restating something, not adding value.
Here are some examples:
• "old faded blue shirt" could be "faded blue shirt"
• "…shards exploding like shrapnel shooting across the room," is crisper as "…shards exploding like shrapnel."
• "She shuddered as her shaking fingers…" is better as "Her shaking fingers…"