Generally Naut is a brilliant jungler for controlling team fights, initiations and has a pretty quick clear time. He brings an amazing amount of crowd control as well as tankiness to the party.

Look there is not much to explain here. I have found that Naut is probably one of the strongest counter ganking junglers in the game, due to his utility and fast clearing times on the smaller camps (wolves & Wraiths) he is able to help play the ward game, which in turn if warding correctly can allow for easy counter ganking as well as counter jungling. Look im not saying his ganking isn't amazing o_O. I mean level 3 Naut ganks are amazing if played well.

Initiation - This is one of Nautilus' strengths so use it properly. Firstly remember you have a gap closer with your "Q". Secondly your passive gives a 0.5-1.5 sec snare. Thirdly and most importantly remember that your ultimate has a travel time of about 1-3 secs depending on the enemies reactions, so you need to cast your ultimate within reason (Nothing worse than blowing an ultimate with no reward, and I don't consider blowing the enemies flash as a reward, that should be a given).

Prioritize Targets - Always make it your goal to distract/focus the most dangerous enemy player, within reason. I'm not saying chase the enemy ADC cross the map. I'm saying control/restrict the targets movement during fights and skirmishes. Another good thing to remember is the time your ultimate, Naut already brings amazing CC to the table so rather engage with "Q" and wait for enemies to stack up before you use ultimate that way it can be used to full effect.

Tank - The last point at first glance seem like an easy one but there is a big different between taking unnecessary free damage or vitally Soaking up damage for the team. This skill generally only comes with experience but here is my little tip. There are 2 very easy ways to tank effectively for your team. One is to stand on one your most valued players (MVP-generally ADC or APC) and peel for them. Now peeling means to protect while blocking enemy CC and damage from your MVP. Secondly is as discussed before sticking to the enemy MVP and forcing them to direct there focus onto you so your team has a little more freedom in a fight.

WARNING - Remember this when ganking your "E" can cancel auto attacks so wait till you have snared your target with your passive before you use "E"