hi, for my subI i also found it very helpful to have a pen light, and something to distract kids with/use to see how well they follow, etc. I also had a card that i photocopied from a book with basic lab values and vitals for age (warning, maxwell is nearly worthless on peds- or at least i think so)
other than that, keys to being basically good at my institution included:
1. problem #1 is health care maintenance, find out who their primary is, including phone and fax numbers (to fax d/c report), if they are up to date on their immunizations.
2. always at least skim through developmental milestones
3. if its a baby/toddler, find out BM vs formula vs. solid foods, make sure age appropriate.
4. no matter how well i knew a topic (or if i just admitted another kid with it that week) i always read nelson's (which is online for free at my institution, and most likely at yours too)
5. if its an NICU grad, try to get the discharge summary, or find out any major complications, make sure they have proper f/u (i had two that had be lost in the system, and we got them reconnected with pt/ot, etc)
6. try to communicate well to the parents, its good practice, and they really appreciate it, some of them appreciated literature about new diagnoses, and sometimes they just want to ask you the same question one more time to make sure they understand (but of course, don't talk over your head, in the event that they ask questions you aren't comfortable answering, decide if this is a topic you can breech after some talking with your senior/attending, or if this is a conversation better left for an attending in which case try to be present for the conversation)
remember, that this is supposed to be fun!! it's nice to have a glimpse of what your life will be in a bit, work hard, but relax. good luck!!