Switching schools can be necessary evil, and the need often happens in high school. Although changing schools in younger grades can be emotionally challenging, changing high schools brings on a whole new set of technical difficulties, especially if moving to another state or transferring to a different school type. 
First of all, a high schooler needs to accurately record and get credit for all his high school courses on his transcript. Switching schools so late can cause some teens the headache of having to re-take course credits to satisfy their new school's requirements. This is often unnecessary, expensive, and a time-spender that can easily avoided by planning ahead.
Here are a few tips for transferring high school credits:
1. Know each school's credit acceptance policy inside and out (along with graduation requirements as these may alter school to school)
2. Talk to both schools' registrars about needs (well in advance!)
3. Get all paperwork and forms completed for evaluation ahead of time
4. Deliver transcript and documents as requested by the new school (and withdrawal properly from former school)
5. Try to attend similar school types (or attend an accredited school) to help improve credit acceptance
6. Negotiate credits that don't transfer (schools can be flexible in counting credits for similar classes the new school does offer, especially if a graduation date is in jeopardy)
7. Online high school credits can vary in acceptance by other high schools and college, so ensure credit status before enrolling (be aware online schools can be considered homeschooling by other schools)
8. Dual enrollment credits are available in some high schools and university programs (consider this as an option for saving time and money for earning college credits early)
Have you successfully transferred high school credits from school to school? What tips do you have?