Hi guys!
The two I use the most are strategic use of clubs and community lots. I always create two community lots right away- they cannot be generic for these purposes so I usually make one a museum and one a library.
The museum is converted into a conservatory with a huge kitchen area on one side and an assortment of private music rooms on the other. I will often also make sure that this lot has a number of easels available and the easels I use are the ones that give the highest quality paintings - not the inspired buff. I stock the kitchen area with a large bar or two small ones and one or two stoves and one or two fridges. Unfortunately the cupcake factory will not work on a community lot. The other side of the building with the music rooms, has upright pianos (if you use cc) or keyboards in each one and guitars and violins available. The music side also has available a pipe organ if you have the expansion that uses one.
This lot has the following traits, Homey, Great Acoustics and Chef's Kitchen or Home Studio (depending on whether I am favoring training cooking + gourmet cooking or painting) Other traits to consider for this lot depending on what you use it for could be Natural Light or even Convivial since the idea is to use this lot as a club hangout.
The library I rename as the Science Center. This lot has a microscope, observatory, rocket, chemical analyzer etc.. any giant science object that is ridiculous to be putting in each of your sims backyards. Once on the lot you can upgrade them and they will retain the upgrades. This lot also usually has a large computer room with desks accommodating as many computers as you like, and always has chess tables and of course libraries with training books. Decorate this lot with buydebug items that include crystals and fossils so that when the time comes to build your microscope collections you can get your samples right on site. I also usually include a woodworking table on this lot because it is used in the science and knowledge aspirations. This lot should have the traits Fast Internet, and Science Lair - other good ones are the new trait Peace and Quiet and again stuff like convivial can't hurt (cause you want to use this as a club hangout) and Home Studio if you are working on the writing skill or aspiration.
Next comes the use of clubs. This first one only works if your sim doesn't live alone, but if there are two people living in the household, create a club with no other members except the household. When you are not running another club - run this club (keep it running all the time - even when they sleep). As long as this club is running, it will accumulate points and you can use these points to buy club perks that will make it so that your sims in the household can easily attain any emotional state they need at the moment and depending on how quickly you build those points, they can attain boosts to work performance and skill gains. As long as you stay focused on the household and are running the club, even while the sims are at work they will gain the benefits of this club including retaining the emotion buffs. Once you build up some points you can determine which skills will most benefit your sims and you can buy the skill building boost for the skills you want most.
An example of how this works is this. Adam and Eve move into a new home. The first thing you do is set your house traits to convivial (so they build their relationships faster) and I like the homey trait early on. Next, create a club immediately that includes just Adam and Eve. Even if you set "be friendly to everyone" as the only club activity, any friendly interaction will start building you points. When the welcome wagon starts, spam friendly actions on the guests. This builds your charisma which is boosted by the convivial lot trait. When you build up some points you can choose any number of club perks that will immediately help your sims, such as making the club popular with only 100 points or giving the club a boost to success with happy socials which will help boost your charisma if you do charisma based friendly interactions like "brighten day" or "heartfelt compliment". It will also increase the rate at which you gain points for the club (Even while your sims sleep they gain points while the club is running). Now since you have the homey trait activated on the lot why not make a nice fruit salad for your guests. Don't forget to add cooking and eating as temporary club activities before you begin cooking. Now your club will gain points at an even faster rate as you make the fruit salad and eat the fruit salad. After they finish cooking/eating simply remove those activities from the club itinerary. Next invite a guest to play chess (if you have a chessboard) or watch a movie (if you have a tv) or dance (if you have a radio). Change your club activities from the cooking/eating ones to the dancing, playing chess or watching a movie ones. Your points should be coming quickly and soon you will have enough to buy at least one rank in an emotional boosting perk. So let's say it's the chess board you have - it's a good time to buy the first rank of the emotion boost perk for the focused emotion. Once you've bought it ask your housemate to change the club vibe to focused. Now while you play chess you are focused and will gain logic even faster (if you are so inclined - jump over to build mode and add the science lair lot trait to the house temporarily while playing chess). Now your point building will be increased by talking to the guy you are playing with as well as playing chess and you will have boosts from the lot traits for both charisma and logic skill gains. You will also be getting a boost to logic from the focused emotion, and once you have 400 points which doesn't take that long, you can go ahead and buy the club perk that boosts logic skill gains (it's a significant boost). As long as that club is running you will now have your logic skill gain boosted (this is where a nice visit to the science center comes in). Remember that whenever your focus leaves the active lot with a sim, the club meeting will stop, so restart it when you get where you are going. Also this method works best if you are diligent and not shy about changing your "house" club activities whenever your household changes their activities. So if you go over to the conservatory to plunk at the piano (which you can't afford at home), change your club activity to piano playing for the duration of your visit. The lot traits you put onto that lot earlier will work in tandem with your club perks and if you buy the piano building skill for your club, both your household members can get some really nice, fast skill gains with one visit (don't forget to set the club vibe to inspired before starting your piano lesson).
Once you get your sim a job you want to buy the club perk that allows the sim to gain work experience faster while in a club meeting, then make sure that you set your club vibe to your job's ideal emotional state before going to work, and you gain two boosts to work experience gain - one from being in the ideal emotional state and one from the boost that boosts your work performance while you are in the club meeting. This really expedites promotions and career gains. It also pays to not be shy about keeping at least one lot trait fluid at the home lot and don't be shy about changing it to one that suits your current activity on the fly.
If your sim lives alone the second best way to use clubs to his/her advantage is to join or create clubs that focus on things you can do to build skills at public lots. Don't be shy about creating your own clubs in this capacity, it is this control over the club that will allow you to use the club mechanic to your greatest advantage. If you live alone, you can still use the club system almost as efficiently as the "household club" method by running the club from home basically at all times. If your club members stick around even after you go to sleep or go to work, the club will keep running anyway and you will continue to get the benefits. I've even had situations where my single sim was running a club from home and all the other club member left but the club still registered as meeting until my sim left the home lot.
sorry this ran so long - hope it helps.