It would be best for you to wait till Nov 30 when new update launches and it will be easier for beginner to learn the game and get some gear.
You can solo with NPC Buffs till lv75. After that you need party.
Pick a class that you will like and will be useful in party. Check the skills for lv40-85 and new skills for 85+. Game changes a lot past lv85 as 31 classes are merged to 8 at that point. http://l2gc.com/races/
The game needs dedication, if you want to take part in end game content. ~14 hours weekly will be enough :D
You need clan to get what is best from the game. With couple of friends to play and chat this game gives great experience. The biggest events are clan only. Join clan academy before lv6.
With game going F2P we got some spammers and immature people. You will have to bare with them.
If you want to be in good terms with new players, be nice, patient and listen to advises. Don't demand anything ingame or on forum.
There may be few pve bots per server, but there is so little of them compared to past that you shouldn't worry. The new problem are targeting programs for pvp. GMs don't have solution for that yet.
Newbie Buffs for lv6-75 (Newbie Guide NPC in each town gives them)
No grade Soul Shots (mele) / Blessed Spitit Shots (mage) - they will double damage of your attacks. You need to keep them on shortcut bar and turn on autouse by right clicking with mouse, every time you log in character.