Avoid disaster and confusion when reassembling by organising parts, components and screws. I recommend using a magnetic mat which will hold screws in place.
Alternatively you could just lay them out on a table but you run the risk of screws rolling around and getting misplaced.
3. Disconnect the battery
As I say in almost every video, wherever possible properly disconnect all power including the battery to ensure no power remains. While a phone battery may only supply around 3 volts, it still has the ability to damage and short out components.
4. Use name brand parts
Don't always go for the cheapest generic parts possible. Use reputable brands to make sure your device preforms like it did originally.
However be careful of fake "OEM" parts which could be a knock off or a used part. If the manufacture doesn't sell parts to the public its unlikely you will be able to get access to real brand new OEM parts.