If you see a choke point you can capture, beeline for it, especially if you have a colonizer capital ship, and once the planet is yours, consider significantly fortifying the choke point. Securing key choke points like these is very useful: it's easier and cheaper to be able to defend a single choke point than (for instance) be having to attempt to defend 2 adjacent planets. On smaller maps, there are often gravity wells that have only one or two phase lane entrances from the direction of the enemy, gravity wells which the enemy must go through to get to you. Constantly be scouting out your opponent(s): be aware of their fleet's general location at all times, be prepared to fleet up to defend if they come close, or go on the offensive if they're out of position! Having a couple of frigate factories and a couple of repair platforms on your front lines is a good start: the repair platforms can repair each other and the factories if needed, and your factories can quickly build a fleet to fight your opponent. Especially in 1v1, fast initial expansion is often one of the most important keys to winning: acquiring territory close to the enemy, building a fleet, and preventing the enemy from expanding further is extremely important. Unless you happen to be playing with unlocked teams and can ally with your neighbors and live in cramped conditions, expanding more is almost always a better idea.

While the first few minutes of the game will usually be relatively leisurely, you're soon going to run out of space to expand. The game will almost always start with you in a star system with a few other players.

Sins of a solar empire e4x