There are four basic elementary reaction steps used in most polar (ionic) reaction mechanisms.  These steps have distinct arrow pushing patterns you will need to master.

1. Nucleophilic Attack
2. Loss of a Leaving Group
3. Proton Transfers (Acid/Base)
4. Rearrangements

For Radical Reactions we also have these three basic mechanistic steps.

1. Initiation
2. Propagation
3. Termination