「こと」と「の」

I'm having a bit of trouble understanding which one should be used when speaking about an action.

読（よ）むことができない。　←　I can't read.
読むのは下手だ。　←　I'm bad at reading.

So I just want to know when to use either and if there is any interchangeability here. I kinda find myself having trouble deciding which to use when I want to talk about a clause as if it were a noun.

a lot of the time they are interchangeable.

サッカーをすることが好き。
サッカーをするのが好き。

they both mean the same thing. but the nuance is slightly different. but at your level, it's easier to assume them as the same thing.

however there are times when they aren't interchangeable. u want to remember that by adding の, you make that word into a noun. on the other hand, adding こと stresses that word as an event. pretty difficult to understand, so let me give u an example:

let's say you're at a clothes shop. you can say to the shop assistant 大きいのがいい. this basically means "i want the bigger one". however it is wrong to say 大きいことが好き. (the bigger event is better???? - doesn't make sense)

i guess if you think about my soccer/football example in the same way, it might shed some light to about the slightly different nuance.

if u use こと, soccer/football becomes an event. if you use の, the whole thing of playing soccer/football is considered as a noun

サッカーをすることが好き。 (i like the act/event of playing soccer/football)
サッカーをするのが好き。 (i like "playing soccer")

hope that helps