If, only months ago, you found the graphics etc horrible, no amount of mods are going to change that. Oolite is what it is, a retro-game (kinda) which scratches an itch for a certain type of space game player (usually those who were playing space games back in the '80s, but not exclusively). Out-of-the-box, Oolite is a complete game, but it was designed right from the start to be modded extensively. Of course, all mods are limited by what the core game can do/allow. Mind you, there are players who use few if any mods - that's a serious itch. Myself, I sail close to the core's wind, and the mods I use are almost all eye-candy.
Many have been the discussions, some heated, over what constitutes a suitable mod pack for beginners, and opinions vary wildly. Yes, I could recommend a few mods that I personally consider suitable, but I fear it'd be futile. Perhaps I'll put together a list, but that'll have to be later as it requires some thought, and I'm busy at the moment. In the meantime, from the game's start page select Manage Expansion Packs/Update expansions list/Install expansion pack. The first one on the list is Addons for Beginners, which will install a bunch of mods deemed by its creator to be suitable - try that for starters, see if it looks/plays any better.
Whatever you do, it'll be tough at the start.
Most games have some sort of paddling-pool-and-water-wings beginning to ease you in: Oolite takes the rather more Darwinian approach of heaving you straight into the ocean, often with a brick or two in your pockets for luck.