Time machine- full system back ups

I had thought that post the first fulll system back up, the following back ups would only have the added files and latest files not a part of the previous backups, but the second backup was also a full system backup was i wrong in this assumption?

No, your assumption is correct.

In theory, Time Machine relies on Spotlight indexing to verify any file changes. You are correct in that after the first full backup, TM should only backup files that have changed. Actually, it backs up a whole folder when any file inside that folder changes. However, subsequent backups can be large and be due to a number of reasons. One example is if you use Parallels. Anytime to access or make changes to a guest VM, it updates that VM. In turn this is seen as an updated file and TM will back it up. Since these VMs can be many GBs in size, the TM backup can seem to be a full backup.

Also if it is true, how i can optimize the settings such that I only get the latest data backed up?

Well, with Parallels you actually have an option to not back up VMs with Time Machine.

To answer your question more directly. You can't as this feature is already built-in TM.

In theory, Time Machine backs up only items that changed since the previous backup. It also keeps a complex database so that by combing bits and pieces of various previous backups, it can reproduce the state of your Mac completely at the time of any of its retained backups.

It is a Bad Idea™ to go wandering around in Time Machine backups using the Finder, and you must not delete anything, for fear that your entire set of backups could become unusable.

To restore, you use Time Machine.app.

This article, one of dozens by the late James Pond, has a few more insights as well:

.Pondini's Time Machine - Troubleshooting D4. My backups seem too large

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