I like your land shapes, and I think you do the right thing in not changing those too much. However, they make for a world with even wider expanses of ocean than Earth. Also the huge number of large islands in comparison with the small continents makes harder on the tectonics part...

Which, by the way, if you want to get right, you better start from scratch, as your fist attempt was messy. I spent some time looking at your plates and couldn't work any advice to make it work as it is.

Using G.projector (or a couple of oranges / tennis balls / anything round you can draw on) is a very good strategy. Stick to this workflow when at it:
- one boundary at a time (say you start with a convergent one)
- draw the boundary as you want it (you don't need to draw the entire plate)
- mark a big arrow (or a few) on top of each plate showing their movement (since you started with a convergent in this case, movement is towards that)
- on the opposite side you NEED to have a divergent boundary - either deep ocean ridge or a continent tearing apart (ridges are more common)

- repeat this a few times and you'll have almost everything covered, then you work out the side boundaries and the details.

- be sure to do this in a round medium or to check at g.projector a lot of times.