Once your baby is ~6 months old, they are old enough for solid food...here are some products, etc. that we found useful:
Lucie's List has a nice summary of our philosophy, which is "let the baby eat what he/she is comfortable with". Both our kids really wanted to eat on their own, not be fed...so we followed a more "Baby-Led Weaning" method. However, if they had wanted to be fed by adults, we'd be cool with that, too.
We found it easiest to just feed our kids what we were eating—sometimes mashed up or cooled down, but there wasn't any need to make something special for him (other than bananas—good Lord the kids loved bananas!). We tried to expose them to a wide range of flavors, but staying away from sugar. We really liked the advice in Nina Planck's Real Food for Mother and Baby
High Chair or Booster
Inglesina Fast Table Chair (manufacturer's link, Amazon, Google Shopping) - both our kids really wanted to be at the table with adults, so we knew a traditional high chair wouldn't work well...this chair clips to the table, which they loved; also rec'd by Lucie's List and BabyGearLab. Only 2 downsides: 1) it is machine washable but it's a bit of a pain to take the fabric off 2) there is a ~1" gap between the chair and the table, into which inevitably goes some food (they now make the Fast Dining Tray Plus that fills some of this gap)
Wirecutter recommends the similar-looking Phil & teds Lobster Clip-on Highchair (Amazon, they say it's more portable than the Inglesina, albeit somewhat less comfortable), which we haven't tried
OXO Tot Nest Booster Seat (manufacturer's link, Amazon, Google Shopping) - we ended up switching to this when our 2nd kid was ~9 months old; it attaches to a normal chair and thus is more stable than a clip-on...it's easy to clean, comfortable, etc. The only disadvantage is that the straps are short, so if you have a bigger baby, they might outgrow it sooner than other boosters.
ezpz Happy Mat - these are awesome mats with built-in "bowls" that stick to the table. The original Happy Mat is nice (and rec'd by Lucie's List), but we end up using the Mini Mat more, since it fits better with the Inglesina Fast Table Chair (the original fits but only "vertical") and it easier to take on the road (e.g. in a diaper bag). One downside: the Mini Mat does not stick to the table quite as well as the original.
Squooshi - this is a cool product that lets you make your own squeezable food packs out of anything that is smoothie-level consistency: yogurt, mashed bananas, purees, etc. You can fill it with a spoon but it's easier with the plunger Filling Station, especially if you're preparing a bunch of packs. It is plastic, though...
We found the following things to be helpful but the specific brands seem pretty much alike:
Bibs - these help contain the mess somewhat, and are also useful for drool/teething
our friends liked the bibs that catch messes underneath, like the BabyBjorn or Modern Twist bibs, but we ended up mostly using cloth bibs
as noted on the main baby page, our favorite
other folks rave about Ikea's long-sleeved bibs like the Kladdig, since that also protects the baby's clothes
Sippy Cup - good for water or milk, at least at first; some brands we tried:
NUK Learner Cup (sold at most Walgreens)...or a very similar one from Green Sprouts, which was nice
Pura bottles with a sippy top - this is another option if you don't like plastic...conveniently, these bottles also work as baby bottles with a nipple, so you can get a few Puras and use them from birth to ~3 years.
Green Sprouts Glass Sip & Straw Cup is a glass cup with a plastic outside—perfect for stuff that you don't want to react with plastic, but don't want to worry about your baby shattering glass. It does have a *lot* of parts that need cleaning, though. --> Update: we ended up getting rid of this and just using the Puras
Toddler-sized forks/spoons - we ended up mostly using ones we got as gifts
The following stuff may not be for everyone:
Metal cups/bowls/straws - if you don't like plastic, there are various stainless steel options out there but we really liked the expensive but high-quality Caveman Cups brand cups & bowls. For straws there are a bunch of brands; we ended up with this one (sold on Amazon) but there are lots of others. --> later we got these awesome glow-in-the-dark silicone straws from GIR, which were a big hit
Splat Mat - if you have hard-to-clean floors and your baby loves to throw things, these can be useful...but we ended up no longer using ours since it was actually more of a pain to clean than just wiping the floor
You can use a cut-up shower curtain, DIY with "oil cloth" from a fabric store, or get a pre-made one
We had the Prince Lionheart Multi-Purpose Catchall but various other ones looked good, too. Try to get one that can go in the washer (the Lionheart can, as well as the Bumkins one)