As to reading, I usually give people the advice of how to become an equivalent of Jean Bourgain (I'm too old now and has always been too lazy to follow it myself, but I'm pretty sure it is robust). Take a mathematical paper (any paper) and work it through trying to prove the results yourself for a while and then just looking for hints where you get stuck until you reinvent the whole proof of every statement or find a better alternative. Then repeat with another one. And so on for about 20 years.
In the end you will be reading like he did with one of the stories being that he would take an article from some Japanese journal, look somewhere in the middle at some technical lemma, say "Aha, this is the point!" and then go to the board and state a theorem stronger than the one in the paper, after which he would look at some German paper and say "It is pretty much the same as Japanese, but OK, everybody should make their living...". I haven't seen that myself, but some episodes I witnessed came pretty close. Another story about him is that there was an open question solved independently by Bourgain and Pisier, Bourgain using a method from some earlier Pisier's work and Pisier inventing a new one.
They say that Joseph Brodsky (a famous Russian/American poet with Nobel prize in literature and other accolades) used the same technique, which in his case was to read the first two and the last two lines of a short poem by somebody else and to try to fill the middle by himself. If the result was better than the original, he went to the next one, and if not, he worked it through thoroughly.
You should understand, however, that this technique (understanding each paper you read better than its authors) is most effective if you want to become a "problem solver" rather than a "theory builder". If you care about how something is proved more than about what is proved and if you classify the theorems by the underlying ideas rather than by their context and connections, this style of reading is for you. If you are the opposite kind, you'd better follow an advice from somebody similar to you in their inclinations and attitudes towards mathematics.
Why am I not following my own advice myself? Just because I'm utterly lazy. If I read at all, I do read like that and it usually benefits me quite a lot, but I don't do it often. My substitute for reading is just talking to random people and trying to think of their problems together with them if they are able to translate them into the language I can understand. Under no circumstances would I try to gobble a huge volume of material in short time just for the sake of it just because I have poor memory and if I try to do it like that, by the time I open the fifth paper, the first one will completely evaporate from my head. This is also the reason that I skip most conference presentations (or sleep through them if my friends convince me that I should be present) and go only to a selected few that I can understand and remember afterwards.
In summary, my opinion is that if you bother to read something at all, you should absorb it completely so that you can remember it a few months (or, better, years) afterwards and, if the occasion arises, be able to use the learned techniques of a fresh problem immediately. If that is the case, your reading style is fine for you whatever it is. If not, you may consider changing it. The reading speed should come naturally with time and experience, not to be forced.