There will be times when the garden's the last thing you're thinking about. You're sick, or you have a major deadline or you're on vacation. When you walk out the door again, the place has turned into a jungle. You could call a professional to spiff it up again, but if you want to do it yourself, here are the first steps:
1) Shave the edges. A neat, clean line improves the look of any bed, no matter how messy.
2) Cut out anything that's dead or dying. Be merciless. You don't need anything that keeps you feeling guilty. Sometimes this is just cutting back a perennial to the ground, or removing dead branches. Sometimes it's taking out anything that's beyond help. Give yourself a fresh start,
3) Do a quick weed-through, pulling out the tallest, most visible weeds and leaving the little ones for later. Set yourself a certain amount of time, maybe half an hour, maybe even just ten minutes. You won't feel so overwhelmed if you know there's an end in sight.
Now, give yourself some time to relax and step back to look again. Much better, isn't it?