So here are some great tips on grooming and looking good.
Before you leave the house:
Take a shower every morning
There's just no excuse for missing a shower when you wake up, before you go out for the night or after a workout. Water, soap, towel. Simple.
Check your face
You don't necessarily have to shave, but at least ensure that your face is clean and free of "debris." A quick look in the mirror to check for nose hair, stuff in your beard or crust in your eyes doesn't take more than a few seconds, and is well worth the effort.
Groom your hair (ear, nose, chest, head, etc.)
Hair growth happens with regularity, so make trimming and upkeep part of your routine. Wash and condition your hair every day (or every other day, depending on your hair type and length). Set aside one day a week (preferably a Saturday or Sunday, when you have more time) to tend to ear, nose and chest hair.
Clean your hands
In the business world, handshakes can make or break you; in the dating world, a woman expects to see nice hands. So all you have to do is cut your nails regularly, scrape away the dirt with a "nail cleaner" or a nailbrush (which you can keep in the shower to save time), wash your hands frequently (to avoid sweaty, sticky hands), and use lotion on occasion (to keep them smooth).
Apply lip balm
There is nothing worse than looking at chapped lips, and trust me, no girl will want to kiss them. Find a good lip balm and use it regularly. Just don't put too much on, or it will end up looking like lip gloss. And if you don't like applying it in public because of the unmanly look it portrays, then do it in private when you go to the bathroom.
You don't need a suit (unless the occasion calls for it), but you should always wear clean clothes that are wrinkle-free and smell good. In other words, wear clothes that were just in your drawer or closet, not your hamper.
On a related note, select clothes that fit. After you put on your clothes, take a look in the mirror for a few seconds to make sure they fit properly. Yes, their preferred fit will vary over time as styles change (along with your body and taste), but the key here is to pay attention to what you're putting on.
Use some sort of scent
Many guys go to town wearing some sort of fragrance, using everything from scented soap and deodorant to aftershave and cologne. Other guys prefer not to use anything. Like most things in life, the answer is moderation. Pick one scent (otherwise you'll combine fragrances, which will result in a weird smell) and go with it. Just make sure it isn't too strong and make sure not to bathe in it. A sample scent most love by men is Polo Sport from Ralph Laruen. One final note: Don't skimp on cost here; cheap cologne will act like repellant.
Shine your shoes
People tend to look at your shoes right away. If dress shoes are appropriate, make sure they're shined. If you're wearing casual shoes, make sure they look clean and new. Tattered shoes tell the world that you either don't have money or don't care -- neither option is attractive.
Once you're out:
Have proper posture
Good posture is important for you and your appearance. Focus on sitting and standing up straight. If you need a little extra help, do some posture exercises to strengthen your core muscles.
Scan your attire
Throughout a long day at the office, your clothes are likely to shift and get stained. After lunch and maybe again before you leave the office, check yourself in the mirror or look down to see if any adjustments are in order. As a side note, an untied tie is not a good look -- either keep it on or take it off.
Check your smell
Sweat happens, but it's also the enemy. Take a whiff of yourself every few hours and keep some fragrance (cologne, deodorant or body spray) on hand to freshen up. Also, if you sweat a lot, consider wearing an undershirt to prevent getting sweat stains on your shirts. To make sure you smell good from head to toe, apply talc powder on your feet to stay dry, especially if you're not wearing socks with your shoes.
Perform a quick facial check after you eat
Take a few minutes and use the bathroom mirror after you eat. Scan your teeth, nose and facial hair for any evidence of your meal or beverage. Ideally, you'd also brush your teeth, but if that isn't an option, then use a toothpick, mouthwash, gum, or mints.
You'll be judged by your cover:
If you look good, you feel good, and if you feel good, you give off those vibes that tell the world that you feel great. Make your impressions count by letting your appearance show off what you have going on inside. And make frequent use of those mirrors. You don't have to be a woman about it, but you should check them as often as you can.