to clean the screen of your laptop don't use those products that say (laptop screen wipes ect.. they're useless they leave marks on your screen) for screen, the product (glass cleaner liquid spray) is perfect the ones for home use. ask your mother for it. use kitchen rolls paper wipes (not the small toilet ones) the thik ones when you use for spilled tea water ect...
to clean the outer case, use any foam cleaning product that doesn't leave greace there are many computer foam cleaning cans. again use a paper big kitchen roll for it.
to clean the keyboard, get your house hoover (vacum for usa) and just suck up everything after you're done spray the foam cleaning on the paper roll and clean the keys gently any force will take the key out.
don't clean the battery, take out battery and ac adaptor whilst cleaning, when cleaning screen spray the liquid on the roll not directly on the lcd, gently wipe one way from up to down, then use a new paper sheet to dry.
that's how professionals do it..I am one. oh spray bodyspray from a distance it takes bad smell.lol
for the heatsink it's a must for a laptop more than 2 years of use, if your laptop has a panel that is under it take it out and use a brush or old tooth brush to clean the fan and inside the heatsink (by removing the fan) if you don't have a pannel then you'll have to rip the whole laptop. my trick is I use my mouth without opening the laptop, it's weired but what you do it block the air vent with your mouth and breath out as much as you can. this blows the dust out...crazy but it works.