Ok, so after all the photos and web stuff and calling and email, you actually find some houses you want to look at. We often didn't do this, but I'd recommend a no-Realtor drive by first before asking for a showing. It saves everybody some time.
From my perspective, these showings were shorter than I expected. A quick walk-through and a "Whaddaya Think?" from the Realtor and that was about it. It all seemed pretty binary, with not a lot of room to say "Well, I like this and that, but not this..." I tried to do some of that, especially at the beginning to help educate our Realtor about what our tastes were, but it didn't really seem to matter.
What did matter was if I mentioned wanting to make an offer. Don't say the word offer around your Realtor unless you want the process to start running on rails right from that moment. I'd suggest thinking about it overnight and getting back to them the next day, with an offer amount in mind. If you just say "I think we should make an offer on this one," and don't mention a number, your Realtor will probably go ahead and set one up for you anyway, with whatever he or she thinks the offer amount and terms ought to be. You'll have to sign off on everything, but stuff can start to seem really final really fast and emotions start to play.
In fact, I wouldn't talk offer at first, but maybe ask the Realtor to shoot you a couple of comp sales for the neighborhood. Think about the asking price in square footage terms and how that compares to the asking prices of other neighborhoods. A house we looked at in our neighborhood that was quite a bit smaller (and slammed to the side and rear-yard setbacks, so no additions allowed) priced at almost $100 a square foot more than the house we ended up buying.
I enjoyed looking at houses. It's easy to get taken in by some particular feature or another, but I liked going down into basements and up into attics as much as the rest of it. I think that surprised our Realtor a little bit, but when the next action to take is probably to make an offer, it makes sense to be thorough at this stage.
Some telltale signs of issues:
1. A hot basement. Basements shouldn't seem hotter than the rest of the house, and 9 times out of 10 if they do, it's because there was a dehumidifier chugging away until the last minute before you got there. Those things cost money to run, you know?
2. Pipes wrapped in tape, especially at the joints. Sure, there's going to be a home inspection, but if the issues look major, just know you'll be pushing for a bunch of contingencies in your offer, including having an estimate done for the work to fix the problem. Our experience of these kinds of things is that the Realtor would often say "oh, just have the sellergive you $XX cash back at closing to fix that." Sure. Except even the estimate you get is likely to be low, so why go even lower by naming a price up front?
3. Icicles on the eaves. If yopu're looking in winter, this is a sure sign of an inefficient attic/ceiling insulation.
4. Lots of fresh paint and a faint cigarette smoke smell. If the smoke is in the carpets and walls, the smell of the paint will fade, leaving the cigarette smoke. We are in the process of removing some 48-year old wallpaper right now and the smoke smell that comes off of it once we wet it down is surprising (moreon that project later).
5. Weird neighbors. Seriously- any junk piles next door, old cars in the yard, creepy kids looking you up and down and wondering when they can get in to steal your stuff? Any shopping carts on the sidewalk? Curtains closed in the middle of the day?
I'm sure there's others, but the main thing I'd say is that the visit to a house should be all about the reasons you wouldn't want to buy it rather than the reasons you would. You can go home later and fall in love with the place. call your Realtor the next day and talk offers, whatever. Oh, and take pictures! No reason not to.