This article should function as a Combat 101 for people new to doing Combat in . It gives a very basic explanation concerning several things you should be aware about before you start attacking. It does not aim to be complete.
There are three troop types you should consider for attack, Infantry, Vehicle and Artillery. Operative is only useful against bases which have more wall defenses than troops as defenses. Infantry is strong against Artillery and weak against Vehicle, Vehicle is strong against Infantry and weak against Artillery, Artillery is strong against Vehicle and weak against Infantry. When attacking you have the basic choice between going for an army of mixed types or selecting one type. Since it is easier to get your boosts for one specific type, most players choose for one type.
It is best to attack with the highest tier troops you have. Some players like to defend their best troops by having some meat troops in their deployment, for example 10% tier 1 when you attack with tier 3. This way the total amount of troops you lose will be higher, but you will lose less or none of your best troops.
Most beginning players think there is a huge difference in strength between the troop tiers but this is not the case. You will not be able to achieve much by just attacking someone with a bunch of tier 3 or even tier 4 troops, you need to work on your boosts via research and equipment as well.
There are a number of different ways to get boosts: hero skill points, research, equipment with emblems, buildings and items.
Hero Skill Points can provide a siginicant bonus and it is crucial that you assign your skill points for the job at hand. This means before going to attack assign points to the combat projects (left side of the tree).
Besides unlocking the highest tiers possible also focus on getting the Attack, Armor and Health of the troop you intend to attack with as high as possible, and also max Troop Health and Troop Attack.
Use complimentary equipment that all focusses on increasing the boosts for your favorite troop type, for example gear that boosts Infantry Attack, Infantry Armor and Infantry Health.
Make sure to equip the gear with complimentary emblems, e.g. if you have gear with Infantry Attack, Armor and Health equip with emblems to increase Infantry Attack.
It is good to be aware of Combat boosts of your buildings. Barrack (Troop Attack), MASH (Troop Health) and Power Plant (Troop Armor) provide extra benefits for each level starting at level 10.
Before attacking you can use an item to give you extra Troop Attack boosts, these items can be purchased in the Alliance Store.
As a general note, do not forget about the Armor and Health boosts when attacking, as Armor and Health determine how much casualties you endure when both attacking and defending.
Attack only with the main deployment that includes your hero to be able to benefit from Equipment and Hero Skill boosts.
The amount of troops you can attack with is very important, this is a reason to upgrade your Command Center as soon as possible if you plan to attack a lot early on in the game. There are also items to increase the deployment capacity with 10% that you should consider using before attacking, assuming you have enough troops. You can purchase these items in the Alliance Store.
Always important to check with your alliance who you can attack and when. It can typically range anywhere from always attacking anyone except for allies to no attacking at all unless approved by a r4.
Fuel is quite hard to come by and before deciding to teleport to suitable targets I would make very sure it is worth it. Better if possible to fight near your hive, even if this means you make some nearby enemies and/or have to march for 10-20 minutes.
Based on the nationality/language of an alliance, you might try to find targets who are inactive based on the time of day.
Scout first before attacking, to make sure the attack is worth it (are there troops to kill, resources to plunder?), but preferably do this when you are close to actually attacking, to minimize the time your target and his alliance members have to prepare.
If you can find some targets that are not in a hive, that is preferred, as they cannot easily be reinforced.
Only select targets you are confident you can quite easily win (significant less troops and weaker troops than you have in a single march, or make sure you have far superior boosts and higher tier), in case of doubt, ask your alliance mates to rally.
That is it for the basic combat tips, let me know if you have questions or want to share information.