Pour sour cream and ranch dip mix into bowl and mix well. Cover and refrigerate while preparing your veggies.
WASH ALL FRESH VEGGIES and pat dry with paper towels.
Celery - separate ribs from the stalk, trim both ends to remove any dried or discolored pieces. Cut each rib into about 3 inch pieces. Be sure that you have removed any dirt remaining on the inside of the ribs.
Carrots - You can use either the pre-sliced carrots or the baby carrots found in your grocers produce section. I would still give these a quick rinse and pat dry.
Cucumbers - wash them to remove the wax finish. You can peel them or not...its your choice. They don't seem to get mushy as fast if you leave the peel on.
Green Onions - Cut the root end off and @ 1 inch from the green end. Remove any discolored or damaged green stems.
Broccoli - Cut the florets from the head of the broccoli. You can leave a little of the stalk on the florets, it acts as a little handle to pick up the floret.
Cauliflower - Treat this the same as you did your broccoli.
Cherry Tomatoes - Just wash these and pat dry.
Radishes - Wash and cut a thin slice off of the root end and the top end. You can slice these if you like or just leave them whole.
Squash - Wash and pat dry. Do not peel. Just slice, crosswise to make "coins".
Onion - Cut both ends from the onion, cut in half, lengthwise. Slice into half-moon shapes.
Colored Bell Peppers - Wash and remove the stem end of the pepper. Cut in half lengthwise anf remove the seeds and membrane from the inside. Slice into strips.
Drain any pickled item used and pat dry.
Using a slightly damp paper towel, wipe of any dirt that may be on the mushrooms. I wouldn't put them in water.
Now, place your ranch dip in the center of your tray. If you are using leaf lettuce in your presentation, now is the time to lay that out onto your tray. Then place groups of your choice of veggies onto the lettuce in an attractive manner.
Cover with plastic wrap and refrigerate until ready to serve.