Excerpts from Jane's Space Weapons Compendium, vol. 26598, issue 3
Space Weapons
Space weapons can be, broadly speaking, categorized into three types: Kinetic, Energy and Warhead weapons.
Kinetic weapons are logical expansions to mass drivers, which is widely used to catapult spacecrafts into space. Utilizing a long pair of electrodes, a projectile is sped up to very high speeds, in terms of hundreds to ten thousands kilometers per second. They do not tend to be very damaging, but at the same time hard to defend against. Defensive fields have a hard time deflecting them, and they are best defended by specially designed absorption armor, which serves to slow down, deflect and transmit the kinetic energy of the projectile to minimize damage. Even then, they are not very effective, and generally useless towards anything else.
Energy weapons started as lasers, but in the last ten millennia weapons based on exotic particles are developed. Immense energy is directed towards an opponent, and usually concentrated at one spot to create a hull breach. Therefore, many ways are developed to defend against them. Special coating is used to distribute the energy and ensure no melting of the hull occurs. More exotic forms, like deflection fields are also used, using a temporal change in space-time to change the course of photons and light particles, like these deadly beams. However, experienced gunners will utilize the shield-training technique, to deliberately use these field to one's own advantage.
Warheads are a nightmare to the unprepared. In space, there is no fear of fallout, and nuclear torpedoes is the basic starting point. Even the smallest of modern spaceships are already city-sized, a well-placed warhead can still transform it into debris. Therefore, a fleet usually employs enough close-in weapons system(CIWS) to track-down these deadly weapons. Fighters can also be used to defeat them at range, or, in addition, defeat the bombers which launches them.
A note on ship sizes
Those who read stories of historical battles on planets might notice how the word "Carrier" is used to fighter-carrying craft. Nowadays, spaceships are not classified by function, but simply by hull size. The difference in tactical maneuverability of different ships are not much different - though their strategic speed is, and even the smallest ship can house facilities for a fighter wing, if that means forgoing other weapons.