Difference between 实际, 现实, 确实, and 实在
I'm going to try and make this as clear and simple as I can:

实际：practical/actual(ality)
实际上："in fact,...."
很实际：very practical

现实：real/reality
现实生活中：in real life
成为现实：to be realized

确实：indeed/really 
确实好：it really is good

实在：really/honestly/truly
实在对不起：truly sorry
这个人很实在：he's really down to earth 

As far as remembering I would highly suggest you understand what each individual character means...most Chinese words are compounds (two words put together) - for instance if we look at 确实 we have: (确 certain + 实 substantial = verified to be true, indeed). This kind of understanding will give you a huge advantage to learning Chinese.