Your best bet is to begin with the tutorial video:
Second step, click on the "New Game" link at the top of the page. Look at the statistics on the puzzle. You'll want a game with a solve percentage above 70%. Since this site has yet to implement a "Select Difficulty" option, we are left with clicking the "New Game" link repeatedly until you get the statistics you want. Once you're happy with the statistics shown, wait for the "Start" link to appear and you can begin your game.
Hitting the "New Game" link, repeatedly, does not affect your solving statistics. These games do not count as attempted until you "Start" the puzzle.
Every puzzle on this site can be solved logically. That is, you should never have to say "What if I make Tom buy the cheeseburger, and see if that solves the puzzle?"
The video shows a couple of advanced solving techniques. But because I like to play puzzles with a solve rate below 30% and average solve times above 1000seconds, I've run into some real beasts. So look into my past posts to see what techniques I was taught to use by some of the better players here. I tried to document, with pictures, the techniques so others could more easily see how they work.
If you run into a problem, do a screen capture of the puzzle, then post a photo of the puzzle. We'll do our best to show you the next logical step. You have 24 hours to solve a puzzle. Unfortunately, we may not get you a solved puzzle within that time.
The people here are very forgiving with me running into the same roadblock more than once. Meaning, the same solving technique that was used to solve a problem I had on one day, was the technique I was told to you on a later puzzle.