Wanting an advice

Hi all ..
Is there anyone who studying organic chemistry can advice me how to study the SN1 , SN2 , E1 , and E2 reactions ??

SN1 vs SN2 is a very important open-ended case study discussion in A-Level and possibly at AS also for some exam boards.

Think of what Sn1 means
- 1st order reaction - single molecule in the slowest step of the reaction
- it has two steps (first step is the slowest)
- it has double hump for the energy profile diagram - with carbocation intermediate in the middle trough
- hmmm...that is a carbocation, from a alkyl halide...how? break C-X bond...how... heterolytic fission...how? on its own obviously (see first point - only 1 molecule in the slowest first step).
- draw mechanisms again and again with different examples

Sn vs En is a common first year university chemistry case study, possibly in A-Level also i suppose.
- aq NaOH in water promotes nucleophilic substitution (hydrolysis) of RX to ROH
- NaOH in ethanol promotes elimination of RX to alkenes

Hmm, why, how? read up on chemguide further, but not before you can even differentiate Sn1 and Sn2.

Now I am sure some textbook reading would be beneficial, as would talking to people, as would chemguide as well.

Good luck.