Healthy Baby
Take him for regular check-ups (schedule them way ahead: pediatricians get booked up fast!)
Keep up with his vaccinations
Make sure everyone in the family over 6 months gets a flu shot
Dress him appropriately for the weather: He needs just one more layer than you're wearing, no matter how hot or cold it is outside
Don't give anyone in your home a pass on frequent hand-washing!

Essentials for a Healthy Baby

What stands between your baby and a bad tummy ache? Or a sunburn? Or whatever nasty cold or stomach bug is going around? First, care on your part, and second, a small arsenal of healthy-baby essentials.

Any supplements you give your baby will depend on whether you're breastfeeding or formula-feeding (infants who are exclusively breastfed may need extra vitamin D); his age (breastfed babies over 6 months may need extra iron); your local water supply (if it's not fluoridated, at some point your child may need prescription vitamins that contain this mineral), and his general health. Your pediatrician will tell you what to buy; until your child has his first molars and can handle all solid foods, only give him drops, not chewables.
Cold dry air saps the moisture out of nasal passages, leaving them more susceptible to any viruses that might be lurking. A drop (or squirt) of saline solution (basically salt and water) in each nostril might help keep your baby well.
In the same way that keeping your baby's nose moist with saline drops can help ward off a virus, keeping the air in his nursery from getting too dry may keep bugs at bay. Vaporizers do it with warm steam; humidifiers emit a cool mist. Both have pros and cons: Vaporizers get really hot (a potential burn hazard); humidifiers are mold-prone (but are fine if kept clean). When shopping for either, look for a unit that's big enough for the room you'll be using it in, that holds enough water to last throughout the night, and that's easy to empty, fill, and clean. You might also consider an ultrasonic humidifier, which uses high-frequency sound waves to break water into a mist.
These will not, we repeat, will not take the place of a good scrub with soap and water, but they will come in handy in a pinch--especially as a second-tier defense against bacterial infections. They aren't all created equal, though: Studies have found that among alcohol-based sanitizers, only those that are at least 60 percent alcohol are truly effective. A few tips: Choose a sanitizer that has a moisturizer in it to counter the skin-drying effects of the alcohol, and if you let any older kids use it, teach them to rub their hands until they're completely dry, so there's no alcohol residue left.
If your baby's eczema-prone (he gets dry, red, itchy patches on his skin), stock up on lotions and creams to help keep breakouts at bay. Choose ones that are unscented, thick (a petroleum jelly base is ideal), and formulated for sensitive skin. Products with oatmeal in them can be especially soothing. For best anti-itch results, slather a layer of cream or lotion on your baby's skin while it's still a bit damp from his bath.
A baby under 6 months should wear clothing that covers his arms and legs, as well as a hat, and be kept out of direct sunlight. That said, it's fine to use sunscreen on the parts of his body that are exposed. Choose one that's formulated for babies (to avoid any harsh chemicals or unnecessary scents) and has an SPF of at least 15.
And if your baby does get a little sunburn (or the sniffles, or a rash)? Don't beat yourself up about it. Focus your energy on helping him feel better (you'll find a list of remedies for colds and sniffles LINK TK). And when he does, you'll feel better too.