Looks pretty good so far. You do have some river issues on the 'southern continents'. A lake may have many sources but generally will only have one outlet (it may start with more but eventually one becomes dominant). I also saw where a river system empties into two different bodies of water, this generally cannpt happen.
You may want to look at Ascension's continent making tutorial, it will give results similar to what you have but a bit more realistic in appearance.