John, the logical next step is to teach the puppy to stand on command.
I usually do this from the SIT position.
With the puppy on your left, in a sit, put the food on her nose as you did teaching the down.
Let her lick it. With your left hand, tickle her gently right in front of her hind leg. You might need to help lift her a bit. The idea is for her to stand up, WITHOUT moving her front feet. As she stands, say STAND, and let her have the treat. Help her stand there for a second as you praise her.
Another great thing to work on at this time is attention. You want the pup to learn to look at your face when you say her name. Do this using tiny pieces of hotdogs. Cut some up, and put the little pieces in your mouth. Yep, in your mouth. You will take all treats from your mouth to feed the pup when you are teaching attention. This teaches her to look at your face.
So, first, get the pup's attention, take a piece of food out of your mouth, and let her sniff it, then take it directly back up near your face, as you say her name. Say YES! and feed her the treat.
You are going to use the word YES as your "marker". This works like a clicker or other noise maker. It lets the puppy know that what she JUST did is what you wanted, and what the reward is for. SHe will catch on fast that you have food in your mouth. ONce she figures this out, and is looking at your face when you say her name, then you change the rules.
Take food in each hand. Show her that you ahve food in each hand, and then stand quietly. Say nothing. Wait for her to look at your face. It usually does not take long, and as SOON as she does, say YES YES YES!! and praise her and feed her several pieces of food. Once she learns to look at your face for a reward, you can shape the attention in many directions. Shape for longer looks. Shape for looking from your left side.
Then I would recommend you start on the RECALL GAME (the post is on here in the training section) and work on getting her to RUN to you when you call her.
Next lesson is to begin teaching the stay. Let me know when you are ready for that one.