Hi Fellow Farmer!
We've been selling at our local farmer's markets since 2009 (really 5.5 seasons already? wow I feel old!)
Definitely do your price comparison shopping with the other local vendors. If your product is essentially the same (organic practices whether you're certified or not, same weight or amount per bunch or whatever) the charge a very similar price. your inexperience shouldn't discount your price unless it really shows. If your produce looks really crappy like bugs got in it and that's not the case with other vendors, then that is something that we discount our prices for. you still have the same costs as other growers (whether you recognize them or not!) just like zjande says! so don't undercut the rest of us!
Lettuces are something we're really careful about in the flavor department. early in the season when the weather is cooler, the lettuces are fabulous for a really long time. This time of year, we may not have it at all because all it does is bolt and taste horrendously bitter. We keep working on techniques to extend the lettuce season for us because we grow fabulous lettuces when mother nature is on our side but at some point we eventually say "it's going to be too hot" and won't even bother taking up the garden space with it. Kale and Chard however we typically can take through the entire growing season here on the palouse in WA (hot days often in the 80-90s and cool nights in the mid 40s to mid 50s typically). If you're in doubt about it's flavor, have another member of your family try it before you bother harvesting your lettuces for market. my hubby is super sensitive to flavor changes whereas I'm not. hence, I typically am the determinere of "good lettuce flavor" here.
For display, let me tell you what we do. you sound fairly similar to what we do as far as veggies go. Step one is check for regulations. We have to keep greens below 41 F which means in the coolers. early in the season if it's cool, we'll display a bag or two so folks can look at the product and keep the rest in the cooler. we hand buyers a bag from the cooler too. we don't have any other items regulated like that for veggies sooo... it's totally up to what you already have/are willing to purchase for displaying and the image you want to send to consumers. we try and avoid using our big yellow plastic harvest tubs for displaying until we start getting large amounts of rolling items (tomatoes, zucchini, cukes, squash, etc.) Lettuce heads, broccoli, cabbage will be displayed simply on top of the table on top of a wet towel. (also, DON"T FORGET A SPRAY BOTTLE! The grocery stores mist down their veggies for good reason!) Kale and Chard go in tubs of water (perhaps concealed in a much nicer looking wooden apple box or similar. Beans look great in natural woven type baskets (common at the thrift store).
For display you need to think in terms of 2 things.
1: customer proofing. Any possible way that the customer can accidentally damage your produce you need to prevent: extra table space in front, display rolling things in some sort of container but not too many so they can handle them without one rolling away, etc.
2: pretty image. If you want to take a picture of it, you're on the right track! mix up your colors (within and between different types of produce)
The last thing you'll want to consider is consistency in your image at market. Use the same whiteboards or chalkboards, display items, tablecloths, etc as much as possible. That way your customers (as you gain loyal customers!) will be able to find you. We have a hand-quilted tablecloth my mother made for us that we ALWAYS use. We also have Dr. Porkchop (a large stuffed pig) that hangs out at the frontmost corner of our market space. (we sell retail cuts of pork too so he's appropriate for that) We've actually had folks not be able to find us when we've forgotten him!
last tip: Make yourself a "Market Box". a designated tub or box that holds ALL of your non-perishable necessities for market: tablecloths, scale, banner, brochures or fliers, pens, bags, etc. that you find you need just about every week. we ended up with 2 boxes: a scale box (with tablecloths) and a Market Box (with all the other necessities, including a bucket of sidewalk chalk for our kiddos and other market munchkins). This year I actually make a third box just for brochures and papers since we now have a number of those too and I want to keep them nice-looking
you'd think that'd be easy, right?
I know i'm rather wordy but I hope this all helps you out somehow! Feel free to PM me if you have any other questions!