Once a year I'm trimming the hedges around my yard - a European hornbeam - to make sure they grow dense, evenly and are in a good shape. I'm using an electric hedge trimmer to do the majority of the trimming and will do finer details and leftovers with smaller, manual shears.
Whenever I'm done trimming and take a view on the results, I'm bugged about uneven cuts here and there, despite my best efforts. The top ends up "wavy" and the front isn't completely straight across the whole span of the hedge either. I find it hard to keep a good eye on straight lines and shapes when standing right in front of my hedges and waving around with a rather heavy electric trimmer. And there are only so many corrections you can do before you're trimming too much.
Are there any good practices I can follow or supporting tools I can use to make my trims more even?