I'm an optimistic Demigodder. I think that with the introduction of 2 new Demigods and some updates to the Custom Game interface, we're going to see a re-surgence in players and open games. One thing that concerns me is that new players to DG often have several bad initial online experiences (e.g get spanked) and decide to give the game up. I think Demigod is a fantastic game and I'd like to do my part to help new players develop some basic survival skills so that the entire community profits.
There are other strategy guides out there, and I encourage people to read them all, but here are some tips for new players that will specifically enhance your survival. The big idea here is that DYING IS BAD. Obviously, dying always sucks - but when you die, you give the opposing team gold and XP which they will use to make you suffer even more in the near future. New players often end up dying quickly (within the first 5 min of the game) and this can often doom your team to a futile, losing war.
These tips will focus on helping you survive, esp. in the early game. They won't deal much with advanced strategy or even offensive strategy. The idea here is that if you're a new player, your primary goal should be NOT TO DIE. You probably won't contribute to the win as much as other players on your team - but if you don't die, you won't be hurting your team's chances.
1. Look for Noob-Friendly games: if you decide to play Custom games, look for game titles that are specifically FOR NOOBS. DO NOT join PRO/EXPERT or even INTERMEDIATE level games. You will regret it. You should also be aware that sometimes players start games that say, "NOOBS WELCOME" but that just means that they are strong, experiencing players and are looking to noob-stomp. This isn't always the case, but it does happen. Really, your safest bet is to start a game yourself - and call it something like "FOR NOOBS ONLY, PLEASE (USA)".
2. Pick Noob-Friendly Demigods: When just starting to play online, I suggest NOT playing with Rook or the Queen of Thorns. I'd even advise that you stay away from Reg for a while. Some have argued that Rook and QoT are underpowered - but even if that's not true, they certainly are difficult to play effectively. A Noob playing Rook is a dangerous thing (in a bad way). Probably the most Noob-friendly demigods are Unclean Beast and Oak. They have high base armor and solid staying-power, esp. with health upgrades.
3. Favor Items: With each game you play, you earn favor points. You can spend these points to buy Favor Items, which can be used to enhance your DG build. Be aware that when you start playing, you might not have enough favor points to buy anything particularly good. Two of the best cheap favor items are the Swift Anklet (450) and Blood of the Fallen (750). Swift Anket increases your move speed by 15% and that will help you escape from a number of nasty situations. Blood of the Fallen gives 800 extra health + 5 health/sec regeneration. Speed and health are your friends, and these two favor items will serve you well for a while. The next ones to save up for depend on what DG you decide to specialize in. For example, if you take a liking to the Torchbearer, Blade of the Serpent (675) is very useful. The Amulet of Teleportation (1125) is also great. One thing that took me off-guard when I first started playing was Heaven's Wrath - a favor item that can tag you from anywhere on the map for 250 damage. This is often a noob-killer, because they don't expect it coming (along with a Snipe from Reg).
4. Shop Items: The key here is survivability: you want to stay alive as long as possible. If you're a general, your best bet is to buy Monk Idols right off the bat. If you're an assassin, take Banded Armor. This along with Blood of the Fallen (see above) will give you +1200 health and +10 health/sec to begin the game. For your other starting item, you can take Scalemail as a nice beginning armor - or wait for few seconds to get enough gold to buy Scaled Helm. The latter is useful for some more mana-intensive builds (e.g. Spit-UB, Reg, etc.). When you have saved around 1500-2000 gold, head back to the shop. Pick up Vlemish Faceguard if you want more mana (Heal-Sedna, Torchbearer, etc.), Hauberk of Life if you're a minion general, or Nimoth Chest Armor if you want to stack health/armor. Don't sell back your starting equipment unless you really need to. Remember, the more you can stack your health, the better. In general, don't worry about getting damage-enhancing equipment (gloves, trinkets). New players benefit more from pure staying power, since it will allow you to periodically make more mistakes (overextend) and not die. Consumables, like health pots, are also very useful. Just don't buy so many that you can't afford decent armor.
5. Stay close to your teammates. Since you're inexperienced, you're an easy target. The best thing you can do to prevent untimely death is to stick with one of your teammates consistently. If you're an assassin, stick with a general (preferably one who has monks). Do not run off on your own and think that you'll help your team by capturing flags alone. It is likely that you will lose a 1v1 match with a more experienced player - even if they're using the same demigod. If you find yourself against 2 demigods, you're going to die really quickly. This rule is important on every map, but especially so on Prison. If you're playing Prison, you should NEVER be alone. Wait for your teammates, if necessary.
6. Use the chat-box to communicate with your team. Pressing [Shift] brings up the chat box. You can, and should, use this to send quick messages to your teammates. Some very useful ones are: 1) OOM (out of mana), 2) Snipe [DG] - use this to ask a Reg teammate to snipe an enemy with low HP, 3) help - calling for help can actually work, 4) shopping - let your teammates know you're heading back to base leaving them alone in the field. Also, pay attention to message being sent from your teammates. They may tell you to concentrate your attacks on a certain enemy DG - this is vital in big scrums that involve multiple DGs. They will also tell you to back off if you're being too aggressive and over-extending yourself.
7. Don't forget to kill creeps. One mistake I repeatedly made early on was running back and forth between flags, trying to capture and re-capture but not taking the time to kill creeps. If you find yourself in a quiet lane (without enemy DG's), take advantage and just farm creeps for a while. You need to level up. Noobs usually find themselves a full level or two below everyone else in the game after 10 minutes or so. This is largely because they're not farming creeps effectively.
8. Play conservative. Don't overextend yourself into enemy territory. A classic mistake of noobs is to pursue enemy DG's too far, thinking they should push an (imaginary) advantage. Good players will attempt to lure you into the range of their towers. Instead, you should use your own towers as a comfortable base of operations. If you get hurt (health at 50% or so), sit back for a while and let your items regenerate your health. Don't re-enter the foray until you're at 75%. If you're out of mana, be aware that you're very vulnerable. If you can stick in a lane and continue farming creeps or help an ally, do so. But if you're on your own (and that shouldn't happen!), you probably should head back to your crystal.
9. Don't attack towers by yourself. Until you're at least level 7 or so. Early in the game, enemy towers are DG killers. You can't stand up to them. Also, be aware that enemy DG's can (and will) teleport to towers that you are attacking. This will lead to a very dangerous situation. Sometimes, your team will want to push a particular lane and will attack an enemy tower early (this happens on Cataract quite often, when your team is trying to capture the opponent's Gold flag). This requires teamwork and coordination. Wait for your creeps to approach the tower, as they will draw its fire. Attack a tower with a fellow DG, esp. one with monks. Or wait until your citadel priests come on the scene to push towers.
Otherwise, don't worry about losing! It happens to everyone. Learn from your mistakes, develop your builds, and keep at it. A lot of players suggest sticking with one Demigod for a while to get decent with it, instead of switching around, game-to-game. Demigod is a great game and once you start winning, it'll feel really good. MOST IMPORTANTLY: HAVE FUN & BE A GOOD SPORT. Don't ever rage-quit - it really pisses off your teammates that you've left behind. Don't pick on other players who may be worse than you. Remember that it's just a game, etc. etc.
Hope to see you online!