These are all great suggestions. Orchard games are fab- they do a nice 'match and spell' one (you want the easiest version, there's a harder one too) and my 4yo DS learnt all his single-letter sounds and how to sound out and blend 3-letter words from that. They also do a lovely alphabet puzzle which we did first, and that's how he learnt the alphabet.
Board games in general are great- they learn counting on, taking turns, coping with winning and losing etc from these activities.
I used to be a teacher of this age group- anything you can do to improve fine motor control is helpful. Threading beads (start an alternating pattern like red yellow blue red yellow blue and see if he can continue it), play doh, drawing circles, spirals and different types of lines (wavy, straight, zigzag etc) using different paints, crayons and pens will get him ready for writing.
In my experience, children start picking up reading and writing when they are ready and your child is still very young. If he's not ready, pushing it will just create stressful associations without much progress. Keep it all play-based and when he is ready, he will start picking it up.
Incidental learning is really worthwhile. Weighing out baking ingredients, counting out the right number of apples in the supermarket, counting how many steps to get home...you can find all sorts of ways to 'teach' him doing your everyday activities.
Less time watching TV if possible and more time playing together. When he does watch TV, encourage things like number blocks, Alphablocks, Grace's Amazing Machines and so on (they don't learn as much from watching it on telly but they do learn something, and he'll learn a lot more from some programs than others. My DS picked up loads of maths skills from numberblocks.)
He's much too young for a tutor.