If you have an old engine or one that you have removed while you rebuild the rest of the car and don't want it to seize as going to use it again or sell it.
1. take plugs out and put some oil down into the bore's only needs a little say about 100ml's upto 250ml's and then put plugs back in just finger tight.
2. leave the oil in the engine don't drain it as keeps the crank and bearing lubricated.
3. turn the engine over by hand frequently ie atleast once every month the engine is out.
4. make sure engine is kept in a dry place and if covering up use plastic but coat the engine in some normal oil so it does'nt rust but will need washing or cleaning of before using again or it will go on fire.
5. when refitted or restarting if stored for winter then turn over on the starter with plugs out until the oil light goes out and depress the clutch pedal as takes some strain of the engine you may need to use jump leads on a running car to aid speed of turning over. The oil should spray out of the plug holes so cover with a cloth to catch it with.
6. if car is turbo'd take top oil feed pipe off and fill turbo with oil but leave the pipe off and turn car over on the starter as in number 5 until the oil start's to flow from the pipe and then refit the oil feed pipe back onto the turbo. Most common mistake is too turn over with no oil in the turbo and it will wear the turbo bearing's and maybe ok but the price of turbo's not worth the hassle of not doing.
7. don't rev it hard from cold but don't let it idle run it at 2000 revs for atleast 10 minutes then it can idle and remember that when it's first drove to take it easy and treat it with respect and care and don't rev it above 3500 revs for atleast 100 miles and basically do a running in period and if turbo car don't bring boost in until done 100 miles plus.
This guide is also practical if leaving idle over the winter if it's a show car or second car that only gets used on nice days except doing number 4 isn't really practical.
Hope this helps