Tips for playing Spy in low player count matches

As a spy, you're best off spending your time working to assassinate the opposing medic. Since the other team has only one medic, it is a huge advantage to your team if you can kill (or badly hurt) the other medic, even at the expense of your own life.

Since this is a competition-level play, you can expect full communication from the other team. You will very rarely fool them into thinking you're on their team. They all should know where everybody is. (Whether or not they really do is another matter). The simplest way for you to be effective is to find a nice sport to Cloak and Dagger, wait for the enemy medic to run by, and revolver or ambassador them from a distance.

Mix up your spots, be unpredictable, and stay hidden. You may also want to spend some time hounding the enemy sniper, depending on his skill level. I've seen highlander teams completely fall apart from a skilled enemy sniper. On the off chance he's razorbacking, the ambassador will be the weapon you want to go with. Mix your disguises, but definitely use the sniper disguise - that class matches closest with this play-style.

I recommend watching demos and studying other players. That's what I did when I was learning competitive TF2 and it helped a lot. You'll see how teams function (or not), where players tend to stand or how they react, strengths and weaknesses, etc. It can be rather eye-opening.

Also be sure to join low pop servers (1-5 other players) and practice surprising them. It can be a good challenge because after the first stab they should be rather suspicious.

Pug/Scrim like crazy. Nothing is better than practice, practice, and more practice.

Load up testing maps (usually starts with tr) and get a feel for exact positions where backstabs open up. You can also test falling down and stabbing and random things like that.

Hope that helps. GLHF.

I know this question is a few weeks old, but while looking over this question, I realized I had some thoughts that hadn't been mentioned.

Don't underestimate the utility of the other two spy watches.

The Invisibility Watch lasts the longest at a flat out run, and can run forever if you continue to grab ammo boxes: 25% recharge from small, 50% recharge from medium, and 100% recharge from large.

The Dead Ringer works well with a friendly disguise in highlander matches... friendly disguises drop a corpse of the class you were disguised as, so you can mislead them by doing that.

Note: Don't do it for a higher HP class, as if you're not "killed" by a crit, it may look suspicious. This also will tip off any enemy spies disguised as your team, as they will see your fake HP meter.

Now, keep in mind that the DR can be also be recharged by ammo boxes, but the recharge rate is capped at 40% for both medium and large ammo boxes.