Tiles are worth different amounts. A solid house or tree is clearly worse than one with icons on it, or a double-terrain tile.

Having said that, each tile is worth a good amount - not just because of what's on it but because it can help you towards your next bonus land!

It's usually worth prioritising bonus lands over a 'safe' placement.

Remember - money isn't worth anything at the end! But running out of money mid-game can be disastrous in a 2p game.

The more players there are, the more you have to 'follow the trends' when bidding.

Bonus land is super-important! (When you make a line of 4.) Without bonus land, 2 is the maximum you can build on your turn, and 1 on someone else's. So 1 bonus is a big deal! The first bonus land can come after your 4th land. Then after 2 more normal placements. Then again after 2 normal placements. After that, every normal placement will trigger a bonus land. So getting those lines of 4 is important and you want to take advantage of that end-game accelaration. So it's kinda important to not fall behind unless you get a LOT of money by doing so and can catch up later.  

If you're unsure which land to build/auction, going for the free option means you keep more money!

Having much money is good, but remember it's a means to an end! :-p