A few pointers...
1- it will take you WAY longer to do than you think (guaranteed)
2- move your fish out of the tank into something that has - a heater - an airstone and a COVER
3- do replace or rinse your sand well
4- do be sure to put your rock down before you add the sand back
5- do have extra heaters, buckets & water you will need more than you think
6- have a cover ready for the new tank, if you don't already. Your fish will get spooked in a new home, they are not as excited about this as you are!
7- write a checklist/plan and follow it
8- do things like pump cleaning, probe calibrating tonight
9- all water buckets should have a heater in them
10- make extra water
11- take pics for us
Good luck with the transfer!!