There are lot of Technical who write code in Axapta but they did not understand meaning of all lines of code only know output of code.
My tips if you relate axapta code with c++ then you can understand it easily. If you understand concept of class and its object means oops concept then you can learn Ax faster.
In Ax code is depends upon object. We can create object for Tables,class,View,Forms,Macros,maps etc. and each object execute on its own value.
If you have very good in pointer concept ,object concept then you can under axapta very easy.
Second thing you should know basic tables in Standard axapta like ledgertable, ledgerTrans, VendTable, vendtrans etc.
Without knowing functionality of process you can not do anything with code.
So I hope above tips can help you to start leaning of Axapta. So good luck.