Somthing ive learned while playing is, it is always good to have one planet dedicated to each mineral and keep these planets close to your home planet for maximum effectiveness
this works really well for research when you have to build up resources and wait for a long period of time you can just pool the resources from your mineral planets to your central planet which when you just start out is your homeplanet which is how it is for everyone in this alliance right now.
The best planets for certain minerals
planets 1,2,3 are best for metal and crystal for the close proximity to the sun so you will not have to upgrade your solar plant as much
Planets 13,14,15 are best for deuterium
at the start of your game any planet size smaller than 100 get rid of it it will do you no good whatsover
try to get planets at least 140-150 in size you will eventually have to get rid of this planet but it will do until you have the resources to build a colony ship after colony ship to get a giant planet
the best planets are 260-300 in size those are keppers throughout the entire time you play ogame(NEVER GET RID OF THESE)
I hope this helped