Honestly I think you should make a new account just for the beginner package. Unless you have some rare UT's that you don't want to get rid of, you should make a new account simply because that package is such a deal.

With the new account and slots you should work on getting a pet with heal and mp heal. Your current baby pet was combined too early and should have a max of 50 instead of 35. Making a better pet isn't difficult. To get better characters, make a wizard or necro. I prefer necro because it is easier to survive without a pet. With this class you carefully get him to level twenty and slowly do sprite worlds. Once you have done enough sprite worlds to max his dex, you should make a pally in the other slot and start working to max his dex. (You can make a knight if you want but I personally believe that pally is far better for abysses). Keep on doing sprite worlds and sell the dex to buy defense. Once you have made enough defense to max your pally, slowly do abysses. Abysses always drop defense and makes it easy to max your other stats.

If you haven't already, bind your nexus key to something close such as 'F'. Nexus whenever you get even below a third of your health. Don't buy tops until you are pimped out with 2 6/8's minimum. Don't do shatters, lods, or any epic dungeons until 6/8. This will take quite a while to max your characters so be patient. I am recommending this route because it is reliable and will work if you are patient and cautious enough.

Your third class could be whatever you want but I would recommend that you use the slot to fame farm to feed your pet. Slvrdllr has a video on how to get decent fame fairly easily from the fame train. You should only feed your pet with items over 300fp for beginning. Good luck!