Deadheading is an easy way to get rid of that old, ugly, faded flower and give the plant some more energy to put some new beautiful blooms on. So you’re going to definitely need a good pair of pruners.
For flowers like roses, daisies, geraniums that have long stems, don’t cut off the flower and leave the stem. Actually take down the stem to that leaf so you leave it a little bit prettier.
Some flowers are more intricate, like lobelia, elysium, and coreopsis, which have lots of blooms. You don’t want to individually deadhead, so just do a light shear and remove some of those dead flowers. Blooms down below are going to bloom.
Some flowers are just spent for the season. There are a lot of spring, late spring bloomers that are done, like bleeding hearts and cape daisies. A hard prune will force the foliage to bloom out, give it a fresher look–no flowers–except for something like the cape daisy, which will bloom again in the fall. So some things just need to get whacked way back.