The biggest hurdle in Dubai is that once you arrive, you have to go through a security check before you can enter the transit area; and this can take a good amount of time - once, it took me 30 minutes.
However the good news is the terminal itself is very easily navigable. Once you pass through the security checks and are in the main terminal - walk up to any reception desk and scan your boarding pass at the barcode reader.
The system will then give you direction to your gate and your estimated walking time.
Or you can simply look up at the large bank of monitors displaying flights and departure times.
If you are on a very tight connection - and your inbound flight is late, you may be received at the gate by airport personnel that will get you priority access through the security line.
If all else fails, and you miss your flight - luckily you are in one of the largest and busiest terminals in the world. Simply approach any person at a transfer desk. They will book you on the next flight, and if there is a large delay, offer you a voucher to grab something to eat.
I can tell you from personal experience - it is very easy - and very comfortable - to spend 8+ hours just roaming around T3.