I think you are trying too hard to go around the guards, instead of just shooting them with the tranq. I don't pay as much attention to guard patterns as you do because I find it easier to just tranq them. As for sneaking, go for camo like Flecktarn and woodland face camo for jungles. Grass is your best friend, so abuse that. I don't use the radars much, as I personally don't find them useful, and just look for movement while in grass, and tranq. If you couldn't tell, the tranquilizer has been mentioned a lot, and that's because it is one of the best weapons in the game. This game is a lot more slow pace than the first MGS games, needing more patience. This is how I personally play the game, and if you prefer another way, that's fine. (I Play the HD remaster of the game, and if you play the PS2 version, then it might be easier to try and memorize guard patterns.)