Too much session and database reading? (general info request on coding)

[Kiluad]

I'm trying to learn how to code the proper way.

 

There's a few things im worried about,but overall im worried about clogging up the server.  so what should i keep in mind while coding, to avoid this?

 

I'm thinking, keep insert and update to a minimum?  as in, when possible, use session to keep track of data until i absolutly have to add that data to a database? is that a correct thought?

 

what about once the data is in the database, how much trouble is it to ask for the selected data inside a database?  should i be worried about overdoing request of data from databases? 

 

on the other hand, should i be worried about having too many sessions travelling around with a user.  why?

 

Im just asking to get a better feel for how to do things the proper way, i would hate to have a website built, only to find out that what i built is only a bat, that would bash the hell out of a server i wanted to put it on.

 

[ignace]

I'm thinking, keep insert and update to a minimum?  as in, when possible, use session to keep track of data until i absolutly have to add that data to a database? is that a correct thought?

 

You shouldn't have to worry unless you are absolutely sure you will make the 1M visitors/day (exaggeration intended) mark in that case you will need to adjust your app architecture to be able to scale-up/out and make your app so that certain pieces/areas of the app can be moved to a different server